A buttocks that is as wide as the span of the hands on a clock when it is 3:45. This phrase can be heard in the Beauty and the Beast skit on Saturday Night Live.
Bart: That girl I had a date with last night... Her butt was too small.

Fred: Well, what kind of butt are you looking for?

Bart: I don't know... I like a 3:45 ass.
by missnewboooootie November 20, 2009
Get the 3:45 ass mug.