Watching my girlfriends masturbate always very exciting for me.
I even remember once during having sex with my that time gf for some reason I started loose my hard-on. I was still in her and fucking her on the floor but what ever I do I was still getting softer. So I get out and told her to masturbate. And she did. She widened her legs and started to masturbate infront of me. 1 minute later I was again in her with all of my glory
Unfortunate for me love of my life who is also my wife right now is very confidential about her masturbation. I know she does it but she strictly refuses me to watch her. This is her only closed door to me. She does almost everything from swallowing to facial, public sex and even ok with swinging (still trying to find for a suitable coupe though) but masturbation... She says its her very private and she wants to keep it to herself. I'm only hoping one day I'll able to convince her for a nice show