This is a wonderful idea, thanks for taking initiative on it.
I try to build in natural branching point to many of my chapters. Here's a few (of many) that I would enjoy seeing continued, with an accompanying 'the story up until this point':
From Party Time (3rd person, past tense):
LESLA: Lesla is a friendless, self-loathing emo girl (emo in the true sense, not merely as a style choice) surrounded by an abusive popular-student crowd. For the first time she is getting approval, but for all the wrong reasons, as she is forced to abuse and degrade herself at a party. No one pays attention to Lesla at this party except when they want to mess with her or she begs to be degraded. No one except head cheerleader Eva and quarterback Trevor, that is, who hang the threat of blackmail over her if she stops performing for their party. Armed with a fluffy-pink-topped magic marker up her ass, a leash, a collar, and sporting various humiliating body writings that will keep track of how much she is getting abused over the night, our emo heroine slowly discovers a masochistic side to herself as she is forced to degrade herself for the pleasure of her betters. Some continuation suggestions:
She is allowed a moment to get herself cleaned up - After her initial abuse, Lesla has been allowed to get herself clean. Time for more!
She took a little too long - Lesla took too long getting herself cleaned up. Now she's set up to accept piss into any of her little holes, and gets a special magic marker star to keep track of getting used in this manner. Time for more, now accepting piss!
TERRA: Terra is a physically and mentally strong 27 year old man-hating woman at a frat party. She's there to protect her younger sister Beth but, uh-oh, she didn't so such a great job! Now she has to do what bad boy Doug and his flunkie Jay say, or watch her younger sister suffer, and suffer herself. Some continuation suggestions:
She is encouraged to submit - Terra and Beth have been through a lot already. Maybe if Terra suppresses her pride and just submits to whatever the cruel boys say she and Beth will be spared a worse fate.
And then some - In this branching Beth is okay, but Terra is not! She went and got herself way drunk and passed out in a secluded room. Now she's too drunk to defend herself as two chubby loser boys (calling each other 'L' and 'R') have free reign over her magnificent body, and at least one of them is quite angry that a pretty woman like Terra wouldn't normally even think of getting together with him. L is the more angry one, R appears to have something resembling a conscience, or at least fear of consequence (though not much of either, as it hasn't saved Terra yet!)
CHRIS: WARNING - MALE ON MALE: Chris is a hot little trap with a very dangerous plan to get revenge on his bully Jedd by proving that Jedd is a 'faggot' in front of all his friends. How? Dress as a slutty jailbait girl named Calli and infiltrate Jedd's party! He has a couple branchings - in the Jedd-focused branch he has made his way to the party and recruited a couple unaware losers (best friends Swag and Mark) to maybe help him, though it's hard to tell what help they might be when both want to get into his apparently female skirt and have no idea that he's male or what his plan is.
Kissing games and a better party atmosphere - Chris has finally located Jedd at his party, in a cellar adjoining Jedd's house. Inside is a full service bar and a multitude of impressively thought-out sexy party games. With Swag and Mark in tow, surrounded by Jedd's posse and other partygoers both male and female how much trouble can one sissy trap get into down there? (hint: lots) Can he succeed in his crazy mission? Can he keep his secret while playing games like strip poker and 7 minutes in heaven?
He gets an offer for spin the bottle he can't refuse - As above, only Chris is primed for a session of spin the bottle with the girls... or seven minutes in heaven with Mark and/or Swag if he spins himself