OMG
i never done this but my ex was Bi and tried everthing with the best mate (man ) exept penertion even to the point of showing his partner how to BJ him and a night with just her
I was not with her at anytime THIS HAPPENED and her thought were no to 3sums unless you dont love the person you are with
that was her thought and i cant say anymore as i never been there done it
but if i did would have to be Two girls as and not the back