The hand gesture of flicking one's wrist, typically done by gay men while speaking.
Jessica: Look at these new earrings I got!
Phillip(faggot): O. M- GEE! Those r fabulous!! *flicks wrist*
Randy: Did you see Stephan last night?
Zak: Yeah, what a wrist flicker!
Bill (Talking to his friends): I cannot believe what Katie did! What a whore...
Hassan: Oh-my-jeez, Bill, chillax ya know. I don't think Katie meant it in that way! *flicks wrist*
When nothing more needs to be said, and two people, who lack any formal or street training in any form of fighting, will have wrists bent back and forth in a slapping like motion against each other, usually slapping the face or upper torso.
A dude: Did you see Professor Tay-kit fighting with Jack Whisegy?
The Dude (AKA Duderino): Yeah Jack didn't stand a chance against Tay-kit's innate wristicuff abilities.
a dude: Wrist-a-what?
The Dude: Wristicuffs, the dude abides.
Where ya gently grasp someone's wrists in yer hands and softly clap his palms together in a varying rhythmic "cadence".
Wrist-clap is mostly popular with small children, but cute chicks sometimes enjoy having a nice guy perform it with their hands, too; it's a simple form of playfully expressing affectionate tenderness.