Usually used to refer to Japanese animation named at adolescent girls; when a male character is naked or topless for no reason other than the enjoyment of the viewer or reader. Derived from 'fanservice'.
Fangirl #1: Did you read that one Naruto doujinshi?
Fangirl #2: You mean the one where Naruto and Sasuke got naked, and then they did it?
Fangirl #1: What excellent manservice!
Fangirl #2: I wholeheartedly concur. Now let us squeal annoyingly to celebrate this wonderful event.