How do you tell if you're making love to a nurse...

Q: How do you tell if you're making love to a nurse, a schoolteacher, or an airline stewardess?

A: A nurse says: "This won't hurt a bit." A schoolteacher says, "We're going to have to do this over and overagain until we get it right." An airline stewardess says, "Just hold this over your mouth and nose, and breathnormally."