A Nightcap - a sneaky way to say you’re going to have sex, but you’re too

a sneaky way to say you’re going to have sex, but you’re too shy to admit it

He said he was going for a nightcap, but I know he was going for a nightcap and a half

She said she was going for a nightcap, but I saw her walking into her apartment

I told my mom I was going for a nightcap. She said, 'Good. I hope you don’t come home with a hangover and a boyfriend'