"Baby-Bottle-Nipples"
A fellow is going on a tour of a factory that produces various latex products.
At the first stop, he is shown the machine that manufactures baby-bottle nipples. The machine makes a loud hiss-pop! noise.
"The hiss is the rubber being injected into the mold," explains the guide. "The popping sound is the needle poking a hole in the end of the nipple." Later, the tour reaches the part of the factory where condoms are manufactured.
The machine makes a noise: 'Hiss. Hiss. Hiss. Hiss-pop!"
"Wait a minute!" says the man taking the tour, "I understand what the 'hiss, hiss,' is, but what's that 'pop!' every so often?" "Oh, it's just the same as in the baby-bottle nipple machine," says the guide. "It pokes a hole in every fourth condom."
"Well, that can't be good for the condoms!"
"Yeah, but it's great for the baby-bottle nipple business!"