Well I believe that sex is more than the pure act of coition so masturbation with each other is a great way of discovering more and more of beautiful sexuality and even explore more things that in other situation would never happen.

Thats my point of view and well about literature, I don't have an exact book or something... you can use Internet, books, everything that helps you extend your possibilities, but always use them as complement not as the unique truth.

Hot, and educational. (A foolproof way to know how to get your partner off is to watch them do it to themselves.)

Also, you can always consult the bottomless pit of masturbation knowledge... http://suicidegirls.com/groups/Masturbation/

Definitely hot. Shows your partner exactly what you like!

Hot. And possibly more intimate than sex anyway.
Many, many more people (in my experience) have sex but would enver masturbate in front of their bf/gf.
So long as your pair are having fun and getting off on it, you carry on

Dude!!! DEFINITELY HOT!!! Don't even get me started on this one k

You are effing hot!!!

Hot......Useful in gaining knowledge,,,it can be foreplay,,,,or afterplay,,,,
or just playtime....you could have a wankathon,,,,to see who is better at it...hehheh
mhef