An impromptu pint of beer, unplanned and executed in between or after existing obligations, the having of which is often later denied.
'Pint' is often substituted with the intended volume of Cheekys to be consumed, or dropped completely when used in an informal, familiar environment.
Fancy a Cheeky Pint?
Let's go for a Cheeky.
It's 3 o'clock, time for a Cheeky Six.