A guy goes into a store and asks the saleslady for some profilactics. She says "what size?". He doesn't know so she suggests he go out back and put his shlong in a hole in one of many holes in the fence and tell her which hole fits his shlong. So he gives it a shot and when he puts his shlong in one of the holes, the saleslady goes behind the fence and pleasures him orally making all kinds of slurping sounds and motions. After finishing, he comes back in the store and she asks "well, what size?" He says "I don't know what size, but I'll take a yard of that fence".