Great thread.
We're still relatively new at this, so the first few meetings are still fresh in my mind.
My wife had always been VERY inhibited about sex, from everything from her choice of clothing to using sexy language.
So.....
I think hearing her simply moan "fuck....fuck...fuck.." as she's being pleasured is a big turn-on.
Occasional eye contact with me as she's on the wanton edge of an orgasm is another thing.
I also like when her and her play partner are lying there and she just starts fondling his big dick, rubbing her hand up and down the shaft. I actually think I like that better than watching her suck his cock.
During their sex, I like to sit or kneel at the end of the bed and face her while she's being pounded from behind. She's looking right at me and I'm looking at her, and I can see the lust on her face and I hear her tell me how good his dick feels and how deep it's reaching and how much she likes/loves his cock.
Last thing: I like when the black guy talks dirty to her, telling her what a slut for black cock she is, and how he's going to bring some bruthas over to get some, etc., etc. (No gangbangs yet, but the talk is sexy).