Two doctors have sex

A man and woman are at a bar having a few beers. They start talking and soon realize they're both doctors.

After an hour, the man says, "Hey, how about if we sleep together tonight? No strings¹ attached."

The woman doctor agrees to it.

They go back to her place and he goes in the bedroom. She goes into the bathroom and starts scrubbing up like she's about to go into the operating room.

She scrubs for a good 10 minutes. At last, she goes into the bedroom and they have sex.

Afterward², the man says, "You're a surgeon, aren't you?"

"Yes," says the woman, "how did you know?"

"I could tell by the way you scrubbed up before we started," he says.

"That makes sense," says the woman. "You're an anaesthesiologist, aren't you?"

"Yeah, how did you know?" asks the man.

The woman replies, "Because I didn't feel a thing."