To allow for more than the maximum suggested persons to ride in a car, as clowns do in the circus. Generally when there are more people in a car than there are seats.
"Damn its coldoutside, the 8 of you guys shouldnt be walking, get in my whip, we'll "clown-car" it tonight.
the act of trying to place as many penis' as possible into a single vagina like many clowns try to fir into one car somehow
there was a 20 some going on in bed last night so i was like da hell with it lets just play a friendly game of clown car sex (: but then her vagina tore.... o well
The effect one gets when there are 15 or more people in a single elevator, effectively causing it to look like there are a bunch of clowns in the elevator.
Person 1: Dude, we all look so stupid in this elevator