A Sexual act in which a female sits in the street (or sometimes gutter) while performing fellatio on a male, who is situated on the curb. Hence the name "curb head". This shit is for no one other than the dirtiest of the dirty.
If you are familiar with the exquisite art of road head (the cousin of curb head) you may care to explore the world of curb head.
The term "curb head" was originally created by Emanuel and Terese. So please, don't be jocking our shit.