I have read about girls who recall themselves in those games, "always wanting to be the girl/bottom" or "how embarrassed I was having all the other girls watching me" or "they made me rub between my legs until I felt like I needed to pee", many other expressions of how they felt being exposed, or involved, or placed in an embarrassing or aroused situation. I don't think these early teen or even preteen experiences necessarily lead to, or foster, either lesbian or bisexual orientations in girls, but I think there are many, many girls who get their first taste of their submissive nature during one of these slumber party games, or afternoon parties. Their first taste of sensuality comes at the hand of their friends who are equally naive, or are more brave/brazen (domme?), and they learn how it feels to do someone else's bidding, to perform in a way that pleases someone else.
Many girls have their first experiences of masturbation, or mutual masturbation or even girl on girl sexual activity "forced on them" in one of these group activities. These games go by many names:
Truth or Dare
Truth, Dare or Torture (Australian); with torture being simply for more embarrassing dares.
Lies or Play it Safe
Truth Dare, Double Dare, Promise or Repeat
Truth, Dare, Situation, Stare (India)
Tell or Torture