Wikipedia has a huge amount of info on the different forms of mutual masturbation, if you're interested you can go here.
I'm going to look at mutual masturbation in a D/s role, I think. I'm also going to use frottage in the D/s scene.
This is from wikipedia: "Frottage is the general term for the act of rubbing any part of the body, including the buttocks, the breasts, abdomen, thighs, feet, hands, legs and sexual organs against the sexual organ of another person; this is done whether naked or clothed."
This is a great way to extend foreplay, and I think D/s play can really highlight this. I'm not entirely sure how it will go, but hopefully it'll be hot and steamy - and maybe a little eye-opening for Peri who won't have seen anything like this before. Well, I think that's what will happen! This book isn't writing as quickly as Fridays are coming around - but at least I'm thinking about it and working out how these scenes might fit together (well, that's what I tell myself).