I really enjoy using extremely submissive guys. I don't get turned on my regular bottoms that are really only looking for mutual sex, or worst still those bottoms that only want things done to them that they enjoy.
So for me a slave that is willing to get fucked after they have cum is a big turn on. They need to be a slave in their head and not just in their dick. I hate seeing a slave playing with his own dick unless I have told him to do so for my viewing pleasure.
If I make him cum first I know he's doing things to please me and not himself, I also know it makes things much more difficult for him, so more fun for me.
Spanking, beating and using a slave after he's cum is more fun. As is repeatedly milking his dick. i.e. make him cum once, then keep wanking till he cums again.
When I watch vanilla porn, I much prefer to see the sub with his dick soft, hands well away from it, legs wide apart while some guy with a big dick pounds his hole. Even better if I've just seen the bottom cum first. Though sadly I can't find too many of those types of post orgasm bareback videos.
I also prefer to use as little lube as possible for arse play. Dry finger fucking is fun and seeing how large a
Dildo I can get in them without lube.
I've let to try fisting anyone after they have cum but I hope to one day.
This won't be to everyone's taste, but on two occasions I've watched guys take a dump, wank off over it and then eat their own cum covered shit back up again, which was really hot.