Sit through humiliation

The moment the lights went out, Abby turned towards Sarah and started whispering in her ear. "Let's play a game. If you win, you're free to go for today. If not, we'll go back to my place and play a penalty game." Then, she gave a devilish smirk. "Now, take off that dress."

Afraid of what the other girl would do, Sarah started taking her dress off with shaking hands. As fast as she dared, the girl pulled the piece of clothing up, first exposing her now naked hips, then pulling it over her now exposed breasts. And then, with one fluid motion, she pulled it over her head, once again wearing nothing but her footwear in a public place thanks to Abby. 'At least it's just the two of us in the back row.'

Before Sarah could even think of using her dress for cover, Abby snatched it away and put it in the empty seat next to her. "Arms on the armrests, legs wide." She ordered.

Being too scared to disobey, Sarah did as told, shaking as her breasts and pussy were fully exposed. Then, Abby pulled out what looked like a bunch of tie rips. And before Sarah realized what happened, the other girl had somehow managed to tie Sarah's wrists and knees to the seat the naked girl sat on, trapping her and fully preventing her from covering up.

"A-Abby, please-" Sarah started to plead.

"Shut up." Abby ordered in a dangerous voice before switching back to the more devilish one she used before. "Don't want the few people here to see you like this, right?" Then, she pulled something else out of her purse, and even in the darkness, Sarah could see the shade of pink and the antenna. "Now, here's the rules for the game. Rule 1's pretty obvious, you're gonna sit like this until you either win or lose. Rule 2, you're gonna have to keep this vibrator inside of you the entire time. I'm gonna put it on random, so you won't be able to get used to whatever setting it picks. Now, rule 3 is where it gets fun." She smirked as she inserted the vibrator in Sarah's pussy, ignoring the other girl's attempt to keep a yelp in. "You are not allowed to cum during this movie. If you manage to reach the credits without cumming, you'll be free to go. For now." Then, the smirk somehow turned even more sadistic. "But for every time you cum, we're gonna play a little penalty game of my choosing. Good luck, slut."

Then, with a tap on Abby's phone, the vibrator began moving around, starting Sarah's pleasurable ****.