When the impact of an udder uppercut is so forceful that it renders her unconscious or disorients her.
Riley was riding McMurray so aggressively that she suffered a knocker knockout as the result of a stiff udder uppercut.
She hit my dick with her "clipper knocker" and it felt gooood!
Nathan.H - giving cold callers a titwank at the door
Oh hi, yes I'd like a nottingham knocker
Like the devil's doorbell, but for your dick instead.
Giles: Why are you so happy today, John?
Steven: Last night, Kyle let me wrap the Devil's Knocker.
Giles: Nice!
-or-
Sherry: You look tired today!
Alex: I know, I was up all night ringing the Devil's Knocker.
Sherry: Nice!
A game where large-breasted women take turns slapping a guy's dick with their boobs. Each slap needs to be harder than the last. The game lasts until either the guy comes (he wins) or someone breaks his dick (she wins). Very dangerous.
I left the party because a game of clobber-cock knockers was starting up, and I didn't want to be there for that shit.