I mean, there is you, your female who you're having sex with, and the baby. So wouldn't that be considered a threesome? lol let the trolling start.
the baby is rubbing the uterus. maybe they find pleasure in it? idk i'm not a female, or carry a child in my uterus.
Even if it is a threesome: Almost every parent has had sex during pregnancy. Try not have sex for 9 months with your lover.
That all depends on the size of the man's penis... And on that note I think we have ourselves a rape case, not a threesome... Unless of course the baby consents.
I have actually discussed this while high as tits, me and my pal decided no, because it's like watching 2 people fuck, your not involved. Also the child is not conicious about the sex