so it depends on the girl.
Truth. It's all about the girl, and how she makes it happen.
I also agree with your other points, when you start thinking about the other dick because the woman isn't part of the equation, then it's not going to turn you on. But if it's all about the woman, and she is totally into it, giving feedback, it's all about the team effort on the male part.
For some of us, there is a huge difference between sharing a circle jerk with another guy and sharing a woman with another guy. I wouldn't dare masterbate or otherwise expose myself with another guy in pleasure on our own. But if there is a woman to mutually focus on, as long as the other guy has the same attitude, I see no problem with it.
Same deal on ejaculation. I wouldn't want to mingle my cum with a guy alone. But when I'm in the warmth of a woman, if his sperm was mixed with her lube, it's all the same warmth to me, only extra. I'd have no problem with it. After all, we're already mixing fluids. And who's to say a man's spasms can be any less stimulating than a woman's when all the lovers are one?
by the way: one thing that IS kinda gay is the double anal thing ...
i tried it once and you hardly even feel anything of HER. instead, it is so fucking tight that your dick gets pressed on the other guys' so you hardly feel anything else. the whole stimulation comes from the rubbing on his dick and that is ... you know ... kinda messed up. and even the girl cannot help you with that for she needs to concentrate so much to relax her muscle she will definately not be able to moan lustful or do dirty talking ...
I don't think I could do the double-anal. Hell, I am not shaped for anal in general.
I could do the double vaginal if the woman is large. But I agree, if all you're doing is mashing cocks on their own, without her skin being involved, I'd have a problem. But the penis itself has nice textures and bulges, and when intertwined with a woman, I could find it a good additive in a DP.
I need to focus my lust on a woman, and her warmth. If I have that, I really don't care where any other sensitivity comes from, as long as the woman is part of it. No, that doesn't mean I'd let a guy suck me while doing a woman, I mean being inside of woman with another guy, as long as I am feeling her as much.