Bizz-Buzz! Count the numbers, note which ones are multiples of 3 and/or 5. Doesn't sound that hard, does it? Some people have a harder time of it than others.
Four girls play. Two girls lose. Two girls win, and take strap-ons to the losers. Neat, huh? One of these girls is without question the absolute worst Bizz-Buzz player I've ever seen. Since you can't play Bizz-Buzz with three, she had to stay in after she'd lost all her clothes. First, they gave her a mini-forfeit each time she lost again. Then, realizing that the game might never end, they started ignoring her wrong answers. Finally, somebody else loses and it's on to the forfeit.
There's one small catch. One of the ladies had a boyfriend's birthday that day, and as her present to him involved a lot of sweaty and interesting activities that night, she wanted to be nice and tight for him. So she asked that if she lost, she just get the dildo in her mouth, and since she wouldn't play otherwise and you can't play Bizz-Buzz with three, I agreed. Everybody else's pussies were fair targets for the winners' prongs.