For domination easily buy yourself a strap-on. Or better there are strapless dildos on the market, they also help you feel too if you want to fuck him.
I recently bought a TENS device (electrostim). Get a cheap one for start and there are lots of ideas on the web on how to use it rather than muscles massage.
Add for him a chastity cage on top. If you have any trouble talking kinks with him give him just 2 days in chastity.