【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.