My wife told me she'd love to see me suck her BF to orgasm more than once. She wanted to see us fuck, too, but that part (him fucking me) never happened. 
One beautiful afternoon the three of us were in our bed and her BF had just finished in her while I played with her nipples and kissed her earlobes and shoulders lightly, in general making love to her while she made love to her BF, Mike. As was our custom I was going to take seconds and then go down on her but ....even though the concept of "cleaning" the wife after sex was not something we verbalized as such, I always went down on her at some point after she'd been fucked. I loved it! But this afternoon my wife asked me to "clean" Mike, "before you fuck me" - that's the first time she used that word and it was the first time she overtly asked me to give pleasure to another man. He'd just finished in her ("way to quickly" in her words) and honestly, seeing the cum all over his softening penis turned me on. So without any real experience I leaned over him (he was leaning against the headboard), and held his cock and licked. I knew my wife was rubbing her clit, and when Mike moved such that it was clear that he liked it, I took his full penis into my mouth. His movements told me he liked it and to my surprise I had an erection. We all had a great time that day and from then on mm fun was something I needed (when my wife had her period, Mike would still come to our home, and my wife watched and rubbed herself (or used the Hitachi) as I sucked him to completion. My wife opened that sexy door for me.