Just inside the edge of her bikini bottom, right at the center of her cheekbutt Shrunk in an Amusement Park chapter 10 by Louka31

You scream as she holds you above her outstretched bikini, waiting to drop you in. "Tonya, wait-" was all you managed to say before she dropped you in. You slid down the side of the bikini somewhat before being slammed into the side of her ass as she let go of the bikini, causing it to return to tightly pressing itself against her. You struggle to free yourself: the outside of the bikini bottom is mere inches away, so with a little distance you'd be home free. But as Tonya begins to sit down in the seat, and the pressure on your body begins to increase, you realize that's impossible.

As the ride starts to go up, Tonya raised her ass up and down, methodically flattening you into her ass. You could swear you heard her giggle as your body was reduced to an almost paste-like, paper-thin version of you. The ride suddenly stopped, and seconds later, you felt Tonya's ass rising off of you as the other riders screamed. The ride dropped down. You would've yelled at Tonya if your lungs weren't paper-thin as she slightly lifted herself from the seat, before the ride hit the very bottom with a SMASH and you find yourself practically glued to her black booty.

As the ride ended, and Tonya sat up, you tried to reform your body once more. But with the bikini tightly pressed against you, aswell as the fact that you were just pulverised into her ass, you found yourself having a hard time reforming! You groaned and struggled, but no dice. Any normal person would mistake you for a detailed tattoo at this point.

By now, Tonya had made her way to a water park. She giggled to herself. This little guy was so fun! She was mystified by his ability to avoid being fatally crushed, but found the way he stayed alive as she turned him into the human-tattoo was amazing. So she intended to keep him there for the day, because why not? She pulled back her bikini bottom a little bit to take a look at him. Yup, he was still flat as a board. Before he could scream, she let the bikini slam into him once more, as she looked for something to do...