If your friend asked you to join him in having sex with his girl, would you?

Nope. Mostly because we have vastly different types of women. His ex wife I would charitably call a Ragged Anne doll come to life with the same body shape.

Last time I did it the girl was into it and the guy just wanted to watch his girl get pounded in the missionary position. As I was doing her the BF was encouraging me with instructions. Things like just thrust slowly. Then he said, "time to finish up, really give it to her". It was a bit strange but lots of fun. I was hazy in post nut clarity and he jumped right in for messy seconds.

Only had one MFM threesome, unfortunately. I love the look of a woman who is a bit overwhelmed.

of course, that's what friends are for!

The confusing thing is that in the future anytime you hang out with them you have to be thinking about fucking her again.

Nah. I'm a one partner kinda person.

If I wanted to disappoint two people at once I'd have dinner with my mother in law and her husband.
Yeah but how hot would it be to hang out with this couple as friends and always have the possibility of fucking the wife. Though I guess it would be dependent on how good you fucked her on your first go round.

Depends on which friend, but generally yes.

Been there done that... Several times lol

I was gonna say, this is not a theoretical question for me.
- Ikr ive had it happen at least 3 times unplanned like just happened to accidentally end up double teaming chick that asked to get double teamed or tag teamed. Not ideal cuZ of my extreme sexual aversions to cocks and balls or dudes in general.. When in Rome(and high enough)i guess. It ends wit me just getting sucked off wit my eyes closed and ignoring the xtra homie or just being unaroused and going soft. One time i actually projectile vomited over the back of super aggressive chick that pulled out my dick while i was all fucked up & she asked my homie stared hitting this gross chick from behind on the riverfront one night. Fuckin hilarious cuz i just walked off puking and laughing hysterically while he kept right at it. And she was just some random girl who creeped up on us jamming outside and stalked us around all night long

Well, as a lady I get these offers, and no, I'm not bi, never been into that kind of threesome.

But if it was MFM would you just once want to experience being spit roasted? Seems like something that everyone should try once.
- MFM is my second favorite arrangement, after just FM. Yes spit roasted is fun, DP can feel really good, I like FMM too, where everyone plays with everyone.
  Just not into 2 girls one guy threesome.

No, never.