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Flex Appeal

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It started with a tip… and ended with a twist.

He’s built a following one flex at a time—shirtless workouts, late-night reps, and just enough sweat to keep his subscribers coming back for more. His For Fans Only page is supposed to be easy no drama, no commitment, and definitely no real-life complications.

Until she stumbles across his page.

When the screen pans to a scar she recognizes, there’s no more hiding his secret side gig. Now she can’t stop watching… and he can’t stop wondering what it would feel like to have her eyes on him in person.

What started as a thirst trap turns into something a little too real, a little too fast. And suddenly, the guy who bares it all online might be the one hiding the most.

Small town, best friend’s brother, second chance, secret identity, short and steamy instalove romance.

♥ ♥ ♥

From broke beginnings to business dreams, the real hustle begins after hours. Whether it’s garage startups or late-night gigs, these blue-collar heroes and heroines are chasing goals bigger than the next bill. When love throws them a curveball, they learn that building a future means risking their hearts.

Side Hustle is a multi-author series of short, steamy instalove stories with guaranteed happily-ever-afters. Each one delivers open-door heat, real-world grit, and chemistry that burns hotter after midnight.

95 pages, Kindle Edition

Published January 5, 2026

20 people are currently reading
5 people want to read

About the author

Piper Cook

109 books105 followers
Piper Cook writes sexy insta-love stories with strong, curvy leading ladies and their hot male counterparts. Guaranteed HEA without cliffhangers or cheating.

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Displaying 1 - 30 of 34 reviews
Profile Image for Johanna.
1,373 reviews38 followers
January 8, 2026
This one took me a few days to get into. It was super slow until they spend an evening together not training and the feelings they’ve both had for each other bubble up and over the simmering pot.

He is her best friend’s brother but also her friend on some level. One very sweet evening together turns into forever.


The story is slow until it’s not lol I enjoyed it overall but it felt kind of stilted in some ways also.
3,365 reviews27 followers
January 9, 2026
⭐⭐⭐⭐⭐ Flex Appeal Book 1 of Side Hustle by Piper Cook

Flex Appeal is a fast, flirty, and surprisingly charming instalove romance that knows exactly what it is—and fully commits. Short, steamy, and packed with tension, this story leans into its modern premise while keeping the emotional stakes front and center.

Grey is peak book-boyfriend material: confident online, guarded in real life, and juggling a secret side hustle that’s meant to be easy money—not a complication. His For Fans Only page adds a fun, timely twist to the romance, especially when the secret collides head-on with Kari, who recognizes far more than she should. That moment of realization is the catalyst for everything that follows, and it’s handled with just the right mix of heat and vulnerability.

Kari isn’t just a passive observer caught in a spicy situation. Her curiosity, emotional pull, and internal conflict give the story weight beyond the thirst-trap setup. The best friend’s brother trope adds an extra layer of tension, and the small-town setting makes the stakes feel more personal—secrets don’t stay hidden long when everyone knows everyone.

What really works here is the chemistry. The transition from screen-based desire to real-life connection is quick (as instalove should be), but it doesn’t feel empty. There’s a genuine sense that Grey is hiding behind his online persona, and watching him risk being fully seen—scar, secrets, and all—adds heart to the heat.

As part of the Side Hustle series, Flex Appeal delivers exactly what it promises: open-door spice, blue-collar grit, and a satisfying HEA in a tight, bingeable package. It’s perfect for readers who want a quick, sexy read with a modern edge, low angst, and just enough emotional payoff to make it memorable.

If you enjoy short instalove romances with secret identities, online-to-offline tension, and a hero who flexes more than just his muscles, this one’s an easy recommendation. 💪🔥.

I received a free copy of this book and am voluntarily leaving a review.
2,172 reviews7 followers
January 26, 2026
Kari is stuck living back at home, sleeping in her old bedroom which is now her father’s home office. A couple of months ago her boss was arrested by the Feds. She keeps looking for a new job while slowly working on getting her own social media business off the ground. Her sister Kelly is engaged and living the perfect life. Her best friend Darby has an all -expenses paid internship at her dream job. Darby tells her that her brother Grey is still annoyingly perfect. Kari has always liked Grey.

Grey works for Home Wreckers Construction. He wants to eventually own his own gym. He secretly has a Fans Only page with instructional videos of working out. He never shows his face. He hopes to keep collecting followers to fund his dream. Plus, it gives him practice giving workout instructions.

Kari and Darby talk about Kari finding an efficiency apartment that has a gym. She really wants to move out of her parent’s house and be back on her own. After three job interviews, she stops at a cute apartment complex. It is called Savannah Harbor. It has efficiency apartments available and it has a gym and pool for the residents. Later, Kari goes back in workout clothes with the forms filled out. She wanders around the gym taking a second look. Seeing the complicated equipment reminds Kari why she dislikes gyms. She gets on a treadmill and scrolls for instructional videos. She sees one called Flex Appeal. The gym in the videos looks like the apartment complex gym that she is in. The instructor is the videos has a hot body but never shows his face. She subscribes for the $5.00.

What a cute couple. They both secretly like each other, but neither pursued each other. I could understand because Darby is her best friend and his sister.

I received a free copy of this book and am voluntarily leaving a review.
2,203 reviews14 followers
Review of advance copy
January 4, 2026
This book is part of the multi-author Side Hustle series and it features Grey and Kari's short and steamy best-friend's brother, insta-love, second chance, secret identity, small-town romance. Grey and Kari have known each other since they were kids with Grey protecting and taking care of his little sister Darby and her best-friend Kari. The three of them were inseparable since Darby and Kari were joined at the hip and they were always together. Grey and Kari both have feelings for each other but they never acted on them until Kari is forced to move back home with her parents. Grey has been working to achieve his dream of opening his own gym so he has a side hustle with a Fans Only which no one knows about so he thinks. Grey could only imagine what the Home Wreckers guys would say if they knew it would make work interesting that's for sure. What Grey doesn't know is that Kari has been watching his Fans Only and she recognized him from his scar. When Grey and Kari are telling each other their dreams he asks her if he can tell her something and when he starts telling her about his side hustle she's laughing. Kari then starts saying things implying that she already knows. These two were so cute together they communicated,Grey encouraged and loved her for herself he was very body positive with her which I think is a great message. I also enjoyed seeing the guys from the Home Wreckers series. I would recommend reading this book.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Brandi Jackola.
275 reviews4 followers
January 5, 2026
Kari is once again living with her parents, after the Feds raided the office she worked in. She lost her job, obviously, but also never got her last paycheck, because, well, crime. She had nowhere else to go but back to her parents’ house, where her sister is planning her wedding.

When she sees the bridesmaid dresses that her sister has chosen, her self-esteem goes down the drain, and she thinks she needs to starve herself and work out so she’ll fit in the dress. Ergo, she secretly goes on the hunt for a place to work out where nobody knows her. Grey, her childhood and teenage crush, catches her in the gym at his apartment complex and puts an end to her unhealthy ambitions. He’s got a couple of secrets of his own—like his Fans Only page where he films his workouts but doesn’t show his face, and he’s been in love with Kari forever.

I loved the message of body positivity here. I was a stick-thin kid until my metabolism changed when I was around twenty-two. Now I’m a curvy girl. Took a while to be comfortable with that, and there are times I get angry about how clothing seems to cost so much more when you’re a “plus size”. (I hate that term.) I adore Grey for proving, in words and *ahem* deeds that Kari is perfect just the way she is.

You’ll have to wait a while for the steamy bits, but it’s worth it. The message is this: just be who you are, and your people will find you, even if you have to wait for a decade or so. With Grey and Kari, it’s definitely worth that wait.
Profile Image for Jackie Ziegler.
1,892 reviews8 followers
January 18, 2026
Kari has had a crush on her best friend's brother for a while but nothing could come of it. Even if she is back home and Grey still lives in town.

With her sister's wedding approaching, Kari wants to get in shape. Scrolling social media she finds a content creator who is hot but never shows his face. His workout regimen seems easy enough but she needs a gym.

There is an apartment complex nearby that she is looking into moving to that has a gym and ironically the gym in content creator's videos looks similar. She decides to check it out.

When Grey comes in and kind of puts two and two together but doesn't say much.

Grey has liked Kari, but she is his younger sister's best friend. When she asks him to train her, will he be able to just keep it professional?

Feelings are there but how far will they take it? What if she finds out his secret side hustle? Will she be okay with it?

Will Kari risk love and her friendship with Darby?

Quick read. Good story.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Amber.
847 reviews
Review of advance copy received from Author
January 2, 2026
Grey is saving up to own his own gym, and to speed things up has a side hustle...on Fans Only. He reconnects with his younger sister's best friend Kari at his gym, they spend some time together catching up, and after years of wanting each other, things finally move forward. Only for them to be ambushed by the sister Darby.

This is a short story that was so much fun to read. The characters were all wonderful - Grey and Kari were sweet and swoony together, and Kari and Darby have a friendship that many of us would envy. Darby needs her own HEA, please author! This is the second book that I've read from the Side Hustle multi-author series and I have enjoyed both books tremendously! As I have the author's other books. Highly recommend!.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Virginia.
482 reviews2 followers
Review of advance copy
January 2, 2026
This was the first story I've read by this author and I wasn't disappointed.
It was a quick, fun instalove romance with a well paced, down to earth and realistic storyline with steaminess.
The main characters, Grey and Kari, had me captivated quickly. Grey, the older brother of Kari's best friend is resigned to not acting on the long standing feelings and attraction he has to Kari but life and circumstances align to give them the opportunity act on their chemistry for some page turning heat and spice.
Overall it was a short, entertaining read with a satisfying HEA that makes me look forward to reading more from this author in the future and to check out more titles in the series.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Jenifer.
2,900 reviews6 followers
Review of advance copy received from Author
January 4, 2026
Cute story that sits adjacent to the Home Wrecker's series that this author has. This had a second chance feel to it, even though they never previously dated, but have pined after one another for a long while. I loved the Fans Only spin on the story and that a scar gave everything away. I also loved that Darby didn't flip out when her bestie and the her brother hooked up. That could have made for a completely different book if she reacted differently and I might not have enjoyed that story line as much as I did this one. Can't wait to see Darby get her man finally in the next story. The epilogue gives hints at her story and it sounds like it's going to be so much fun.

I received a free copy of this book and am voluntarily leaving a review.
230 reviews1 follower
Review of advance copy received from Author
January 4, 2026
Flex Appeal is a fast, uplifting read that shines with body‑positive energy. Piper Cook delivers a quick, engaging story that celebrates confidence, self‑acceptance, and the messy, joyful process of learning to love the body you live in.

What really stands out is how naturally the book weaves body positivity into the characters’ journeys. The pacing is light and fast, making it perfect for a weekend escape or a palate cleanser between heavier reads. Yet even with its quick tempo, the emotional beats land with sincerity. Cook’s writing has an easy charm, and the story’s warmth lingers long after the last page.

If you’re looking for a romance that celebrates real bodies, real insecurities, and real empowerment—with a fun, uplifting vibe—Flex Appeal absolutely delivers.
Profile Image for Iris Felix.
28 reviews
January 10, 2026
This book is about loving your sister’s best friend since you were a teenager and finally getting to act on those feelings. Kari and Grey have had feelings for each other since there were teenagers but never acted on them. Because Kari was Grey’s sister’s best friend. They practically grew up together. Grey protecting the girls. When Kari loses her job in Chicago she’s forced to move back home where she runs into Grey and things heat up slowly. Kari is self conscious about her body and Grey has a dream of owning his own gym to help people get in shape responsibly and safe. Long story short…(well it’s a short story) they are perfect for each other. Very well written and a HEA. I recommend reading it.
5,282 reviews29 followers
January 8, 2026
Kari is not living her best life, she is back home with her parents, she lost her job when the feds raided where she worked and now no one wants to hire her. Her sister is about to get married and the bridesmaids dress she is to wear, she believes she needs to lose weight.

Grey has always had a thing for his sister's best friend, when she shows up at his gym at the apartment complex, she claims to be his girlfriend when caught by the management company.

This sparks a fire with both of them, things move quickly as they both feel the same.

I received a free copy of this book and am voluntarily leaving a review.
62 reviews
Review of advance copy received from Author
January 2, 2026
They both have dreams and they have loved each other from a distance. Kari moves home and lives with her parents after she loses her job.
Grey works for the Home Wreckers Construction but wants to open his own Gym. Kari wants to be a Virtual Assistant on social media but works at a call center.
Kari and Grey open up to each other on how they feel. They both admit they love each other and they get their happy ever after!
Love wins again!.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Jean.
1,729 reviews1 follower
Review of advance copy
January 2, 2026
New series with secrets and hidden attractions. Moving back home is the last thing Kari wanted after losing her to be in the middle of celebrating her sister’s upcoming wedding, depressing. Grey has had a crush on his sister’s best friend, Kari. But she is off limits. Grey has a dream of being a personal trainer and opening up gym. He goes about it the only way he can by secretly hosting a Fans Only website to raise money. Secrets are about to explode. Great start to a new year.

I received a free copy of this book and am voluntarily leaving a review.
859 reviews4 followers
January 5, 2026
This was a really really sweet best friend’s brother romance 🥰🥰🥰. The superfine was cute. The nuances of Kari’s character hit home for me…. And I loved how each of the characters actually was super “real”. There’s something honest about reading about characters like these….a good reminder that appearances aren’t everything and even those who you might look at and think “they look perfect, they have it all” have their own insecurities, their own demons and flaws. Spice was mild but the buildup was great!.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Marie.
5,498 reviews54 followers
January 5, 2026
It's not all about his body, except....it actually is!

Grey and Kari are such sweet characters, they both have insecurities and only focus on their own failings, not their successes. Together they find a confidence that helps them grow and see themselves from the others viewpoint, it's not an instalove.... it's a chemistry that's been simmering for a long time, but they are explosive together....hot, sexy and very steamy, I really enjoyed their story and the crossover with the Home Wreckers series. I read this on Kindle Unlimited.
352 reviews2 followers
January 5, 2026
I loved this short but brilliant read. Kari is home after her boss is arrested and not happy about her situation. A chance encounter with her long term crush, Grey, who is her best friend’s brother. Unbeknownst to her, Grey has feelings towards Kari that he hasn’t acted on. Grey agrees to help Kari on her fitness journey and they grow closer until the inevitable happens. Great characters, funny and well written with a nice dose of steam.
Profile Image for Angi.
1,701 reviews
January 6, 2026
Grey has always been in love with his sister’s best friend Kari. He just has never acted on it. When they finally admit their feelings for each other things change. There is one problem
Grey has a side hustle on Only Fans he has to tell Kari about. This is a cute, steamy, romantic comedy that kept me smiling from beginning to end.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Val.
384 reviews2 followers
January 7, 2026
A cute story. Grey has a fans only page where he doesn’t show his face.
Kari watches them thinking something is familiar. As she and Grey reconnect she figures it out. Together they face his sister. Combining their talents to create a life together,” Not shrinking. Not striving to be less. Just… standing where you are and realizing it’s enough.”.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Belinda .
1,330 reviews9 followers
January 8, 2026
Grey has dreams of opening his own gym. Kari has dreams of reinventing herself and fitting into the bridesmaids dress for her sisters wedding. When Kari comes across an Only Fans account that helps people tone their bodies she joins not knowing it is her brothers best friend doing the teaching. This story is a slow burn, friends to lovers, brothers best friends sister story that will give you all of the feels. A wonderful addition to the Side Hustle series.
694 reviews3 followers
Review of advance copy received from Author
January 1, 2026
Loved the way this book brought Kari and Grey together. It definitely was not your typical hook-up. The love has been simmering very slowly over the years. What I really loved about this book though was the message it gave about being okay with what we’ve been given! Great short steamy read with an awesome ending!.

I received a free copy of this book and am voluntarily leaving a review.
12.6k reviews76 followers
Review of advance copy
January 4, 2026
The author has given us a wonderful story that pulls us into the lives of Kari, Grey and her best friend/his younger sister, Darby. The heartwarming story keeps us turning the pages with secret crushes, forbidden desires, insecurities, revelations and steam.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Debbie Benson.
10.5k reviews38 followers
January 5, 2026
I received a free copy of this book via Booksprout and am voluntarily leaving a review. I like how love comes from Kari wanting to get in shape for her sister's wedding. Grey is earning money through Fans Only for his gym and she pieces it together. There is nothing wrong with Kari and Grey proves it to her. I like how they fell in love and worked together to make his dream of a gym real.
3,065 reviews9 followers
January 8, 2026
This was a quick, easy and fun read. Kari and Grey have great slow burn chemistry and a long history of growing up together. They’ve both got a secret or two and are trying to get their dream careers in order.
Sweet, spicy, full of family and a few familiar Wreckers. A great story.

I received a free copy of this book and am voluntarily leaving a review.
1,733 reviews8 followers
January 8, 2026
Kari is back home after her job in Chicago is gone due to her boss and a tax scandal. Her best friend Darby’s brother lives in town and he and Kari are it there’s Ted on each other but keep it to themselves. Grey works construction but on the side he is doing a fitness gig online. Kari runs into him at an apartment that she is looking at. He agrees to train her and one thing leads to another!
Profile Image for C.
369 reviews
Review of advance copy received from Author
January 1, 2026
Short and sweet.
Moving from fear of failure/loss to accepting love freely given.

Making dreams a reality.

A nice and enjoyable way to welcome in the new year.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Karina.
2,354 reviews13 followers
January 8, 2026
I enjoyed Grey and Kari's story. They have known each other for a long time since Grey's sister is Kari's best friend. Grey has always kept the fact that he has very strong feelings for Kari and believes she is the one for him. He has no idea that Kari has always liked him. I also like the fact that we get to see cameos from members of the home wreckers bunch as Grey works with them. I liked the chemistry and connection Grey and Kari have. Wonderful HEA.

I voluntarily reviewed an ARC of this book.
105 reviews1 follower
Review of advance copy received from Author
January 5, 2026
This story truly felt like it could be a real life love story. I enjoyed that it was a story of regular ppl trying to build the dreams they have into reality.

I received a free copy of this book and am voluntarily leaving a review.
Profile Image for Barbara .
7,448 reviews25 followers
January 5, 2026
Before you start to devour this quick read I must warn you that there might be some swooning and facial flushing due to Grey being a HOTTIE. So let Kari and Grey sweep you off into a romantic blissful story worth sitting and reading this book in just a few short hours. It's an OMG page turner.
Profile Image for Amy Hutchins.
406 reviews1 follower
January 7, 2026
Such a cute story. I love that Grey and Kari always had feelings for each other, and then they help each other out in the best way.

I received a free copy of this book and am voluntarily leaving a review.
Displaying 1 - 30 of 34 reviews