A sexual encounter that has occurred in the rear (or the front, if the participants are especially limber) of some motorised vehicle, for example a van, truck, estate car or station wagon.

Can also relate to sexual favours offered by a hitch hiker to one who offers a lengthy ride with minimal questions asked.

Can also relate to sexual favours delivered by a prostitute to a John.
Hey Darlin. Do you like cock au van? I'll bring the cock if you'll bring the fucking van. Ho Ho Ho.

Oi Gary, get the car keys, I'm gagging for a spot of the old Cock au Van.

Listen lads, I need to use the company vehicle this weekend. Ive promised Rita from the the sweet shop a bit of Cock au Van.
by goody5 December 6, 2010
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