A young couple were making passionate love in the guy's van you know, 
shag carpets, big double mattress in the back... all that, when suddenly 
the girl, being a bit on the kinky side, yells out "Oh big boy, whip me, 
whip me!" 

The guy, not wanting to pass up this unique opportunity, obviously did not 
have any whips at hand, but in a flash of inspiration, he opens the window, 
snaps the antenna off his van and proceeds to whip the girl until they both 
collapse in sado-masochistic ecstasy.

About a week later, the girl notices that the marks left by the whipping 
session are starting to fester a bit so she goes to the doctor. The doctor 
takes one look at the wounds and asks "Did you get these marks having sex?" 
The girl is a little embarrassed but admits that, yes, she did. 

Nodding his head knowingly the doctor exclaims, "I thought so, because in 
all my years of doctoring, you've got the worst case of VAN AERIAL disease 
that I've ever seen."