Gel things that go around your wrist. They were popular in the 80's, like Converse, and now they're back! But they are used differently. When snapped, the bracelet is used as a sexual coupon. The meanings are:
Purple: kiss their own sex
Red: lap dance
Green: oral sex on a girl
Clear: whatever the snapper wants
Blue: oral sex on a guy
Black: all the way
Glittery Yellow: hug and kiss
Glittery Pink: also flash
Glittery Purple: French kiss
Glittery Blue: anal sex
Glittery Green: 69
Glittery Clear: touch any part they want (just touch!)
Just because someone is wearing these doesn't mean that they are sexually active or "playing by the rules". They can be used as a fashion statement or as a... you know...
Girl: Ow! Oh shit, you broke one of my black gel bracelets!
Snapper Guy: Hey, you know what that means! (hip thrust)
Girl: Sigh, uh, I don't play by the rules.
Guy: Sure you don't.
Girl: Fine. Come over to my place tomorrow at 10.