look up any word, like dirty sanchez:
 
1.
when after receiving oral sex the guy pulls his penis out of the chicks mouth and slaps her on the forehead with his dick
Man Last night I gave Veronica the wickest penis slap
by swil February 27, 2003
 
2.
when you crack your penis like a whip
i had to get it hard so i did a penis slap
by dont fucking worry about it March 30, 2005