Cockslapping is the practice is slapping someone's face with your penis, usually when erect. Often performed as a joke, when the recipient is either asleep, stoned, or otherwise incapacitated.
John said he enjoyed cockslapping me last night while I was asleep.
AS the title states it is the act in which the pennis is whacked furtively about the famous painting the "mona lisa" often resulting in architectural fapping.
Architect 1: Look that dude's cockslapping the mona lisa!
Architect 2: Yeah, you like that don't you baby?! *fap fap fap*