I love to find a guy who has a wife that wants to watch me suck him off. I'd love to look over to see her rubbing her pussy or have her stroking his...
I've had them and I've had guys fuck me and miss stimulating my prostate; I have a prostate stimulator that, well, it vibrates with differing speeds...
I don't think it's unusual and I believe that it's because once you get to sucking, your focus is on what you're doing to him, which is arousing you...