I have a couple...
The one I've been focused on lately involves a couple that I meet where he is bi and she helps him with it...in fact, she is the one who finds me for him (and eventually her). Her intent, which she tells me at the first meeting while he's preparing the "playpen", is that if he enjoys my cock, the second or third meeting will be devoted to her while he watches. She goes on to explain how excited they both are about having some "fresh" cock to play with.
He then reappears in the room and announces that the playpen is ready. He gives his wife a kiss and tells her loves her. She tells us both to have fun and that she will check in in a bit to see how things are going. She tells me that she is sure I will enjoy myself because she has taught her husband to be an expert cock sucker.
In the playpen, there is a chair with stirrups for my feet and handles to hang on to. It has a horseshoe shaped seat which allows access to all of my errogenous zones. The chair is elevated and there is a stool which is lower for him to sit on. The setup is situated in such a way that when he takes a seat, my crotch is right in his face. He explains that it is the "sucking" chair. Beside the stool is a tray which has various plugs and toys and a large tube of K-Y. There is a very large screen TV in easy view and on it is a very hot FF video.
He asks if I'm ready, which I assure him that I am. He then helps me get my clothes off and get comfortable in the "sucking" chair. He takes a seat and asks if I'm ready. My heart racing, I say, "yes." He then starts playing with my cock and before long, it's rock hard. He is delighted and begins to give me the best blowjob I've ever had, which involves a lot of attention to my prostate.
He keeps me on edge for quite a while, fully utilizing all the toys on the tray. It's exhausting. Once I am close, his wife appears in the doorway and smiles. She walks over and says, "wow, you've got quite a mouthful there, don't you?" He smiles with delight and continues his charge. Both of them can tell by how swollen and hard I am that I won't last much longer. It's full-on head-to-head combat and I'm losing. She asks if she's eventually going to get to try it and he tells her "definitely."
She then reaches down and holds my cock for his willing mouth and tells me that he needs some cum. I of course oblidge. I announce that I'm about to lose it and he picks up the pace of both the sucking and the prostate massage which puts me over the edge. My balls cumpletely drain with a massive orgasm and he has no trouble handling my load...doesn't spill a drop. I almost collapse with the release.
We all sit around and talk for a bit afterwards and she tells me that at the next visit, I am hers.
My other fantasy involves fucking my wife's best friend at my wife's request. She goes out of town for a weekend and asks if I would mind sexually pleasuring her friend. She isn't presently dating anyone and she's a little tired of her vibrator. I agree and she spends the weekend with me and...
That's it!