I assume that this question does not take groups or 3-sums into account. But yes. My record was 3 different people at three different times on the same day. (I slept very well that night!)
No one knows your partner better than you, so simply be sensitive to their needs.
That being said, before you introduce your fantasies, be certain you have addressed all of theirs - be sure. And never - I mean NEVER - ask anyone to do anything you would not do yourself.
Vicki and I were doing an MMF for the first time. I will never forget her words, "Billy, if you enjoy watching me eat pussy, then it's only fair that I can watch you sucking a cock."
I tried it. I liked it. I did it then, and I will do it now. After all, fair is fair.
Oh yes. When I was taking private flying lessons, one of my favorite memories was getting a blowjob while flying. I loved sitting in the cockpit, with my cock in her mouth pit.
For the next question...
Have you ever masturbated in front of a total stranger in public?
Vicki and I were just talking about this today. The possibility of seeing one (or more) of our stories on screen (or available as a video) would be awesome. Our most likely candidate would be:
The Winning Hand With Vicki
Vicki and I write as a team; our stories are true (with an embellishment here and there). The people included in our stories are also real, but their identities are completely changed to ensure their privacy. I do not doubt that Vicki and I could write total fantasy, and we will likely do so at some point. Until then, we will continue writing as we have, and enjoy the side benefits we enjoy (i.e., "celebrating" when a story gets published—something we will probably write about sometime).