Usually a prick named Billy who pretends he has a big dick, when it really is the size of a tic-tac. Can technically be anyone, but it just works better when they're named Billy, m'kay?
Aaron is such a big dick billy, I saw him trying to brag to Christina about his penis size, and I know it's actually tiny because he tried flirting with me by snapping me his dong.
Kid 1: Pretends to suck on an invisible dick Kid 2: *laughs* suckin on dat invisible dick Kid 3: It’s Invisible Billy’s Dick
Kid 2: *laughs even harder*