I had a buddy I sucked regularly some time back who I caved for and kissed after he shot his load in my mouth.
I did it once as part of a MMF threesome where the girl, who was super hot, was really into seeing us guys do each other. I wasn't really into the kissing with him. However, sucking his cock with her help was amazing. I would suck his balls while she sucked his cock and then we would switch.
My wife and I enjoy sucking cock together. She gets really turned on watching us suck each other, then she joins in.