I can easily get aroused while watching a guy mastubate and orgasm.
Most of my female friends say they don't really enjoy watching guys and only do it if they think the guy likes it.
I often find my self alone fantasizing and mastubating about some guy i may have checked out that day imagining they are masturbating in front of me.
Some of my girlfriends tell me they don't masturbate at all (although I think they may be lying) and the 2 girlfriends that do, admitted they do it for their boyfriends to watch as the guys like that.
If a guy is aroused and masturbating it doesnt take me long to get wet just watching.