My fiancé and I have always had a very active sex life, and we enjoy including masturbation as a regular part of our repertoire. The ability to get ourselves and each other off easily using our hands is also a plus because at the moment we still live with our parents. This way we can at least sneak into my room or take a ride in the car.
One of my favorite things to do is have my fiancé stroke his cock while I reach over and lightly fondle his balls or trace my fingers along his inner thighs. He shaves, which makes the view and the feel even more erotic to me. Sometimes he'll also play with my breasts while jerking off, but I derive a lot of pleasure from seeing him simply relax and go into his own world with it. Usually I'll give into temptation, though, and take over stroking his cock myself. I love watching him cum. It's sometimes just as, if not more, satisfying than cumming myself.
Even though I love lending my fiancé a hand, I'm hoping once we move in together to be able sneak up on him during the act and watch him jerk off unobserved. Even though he'll masturbate in front of me any time I ask, the idea of spying on him is very appealing. I know this wasn't a very detailed post, but I hope you enoyed it and I'll try to post more in the future!