fast one—(sl.) a clever and unexpected trick giving the person unfair advantage (usually in the phrase “pull a fast one”):
- The thought that a girl capable of thinking up a fast one like that should be throwing herself away on Eggleston was infinitely saddening.
quick one—(sl.)
1. a quick drink of liquor or a beer consumed rapidly:
- We’ve time for a quick one and then we’ll go and do our bit of business.
2. a brief and brisk sex act:
- I’m not saying that an unexpected quick one can’t be fantastic. … If you’re working a lot you’ll probably need to schedule in time for sex.