Credit goes to the California Clam Slap Connoisseur himself: Mr. B. Fluke of Escondido, California.
When your bumping uglies with a broad doggie style right before filling her pie with your cream you quickly take out your mushroom tipped yogurt slinger and cum in your hand discreetly, but they key here is not letting her know you Busted your load in you're hand, you just play it off and keep going and then a few seconds later you slap her in that makeup caked face with the hand full of semen (she's probably going to start fucking losing it so make sure you're holding on tight) then keep on smashing that ass cause it will then turn into a rodeo until she bucks so hard you fall off. Then run cause she'll be ready to chop off your beloved tallywacker.
I was so hammered last night I pulled a California Clam Slap on that wicked ugly prostitue from behind the sevy.
Used by bus drivers to describe a busted-nut on the floor. Example “Thomas there’s a honking clam on the floor. I know it was you because that’s the seat you were sitting in this morning.”