I guess I've never actually put any thought into why I feel the desire to do so.

I've given a couple, mostly unintentionally, but as has been commented on, they are a "standard" in porn, so I'm sure that plays a part into why. Part also is the "marking of territory" too. Part could be the dominance factor, but also, there ARE a few women that like them.

I met one, one time, at band.........no wait that was a movie.

I have to admit that I really get turned on by the sight of cum dripping down a woman's chin, and onto her upper chest. But then I also like cuming on her tummy, or backside, depending on the position we are in.