Louis and Joyce were making passionate love in Louis's mini van when suddenly Joyce, being a bit on the kinky side, yells out "Oh fat boy, whip me, whip me!"
Louis, not wanting to pass up this unique opportunity, obviously did not have any whips on hand, but in a flash of inspiration, he opens the window, snaps the antenna off his van and proceeds to whip Joyce until they both collapses in ecstasy.
About a week later, Joyce notices that the marks left by the whipping 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?"
Joyce, a little embarrassed that she has slept with Louis (let alone that she allowed the kinky sod to whip her) eventually 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.