As an avid DVP fan, I've done a write up on this just for people like you Chicup Successful DV is in your future if you're into it! To the OP; it's about pleasuring the girl. There's nothing gay about that.
DVP stands for double vaginal penetration and it is FANTASTIC. If you've got a vagina and you're into penetration and totally get off on it, you will probably like DVP. I'm 5'6'', 150 pounds and I've been doing this for almost 3 years. I've done it with smaller than average dicks, average dicks and bigger than average dicks and all combinations. I've seen a 5'2'' 100 pound girl take two larger than average dicks and enjoy the hell out of it. Body size is not a limiting factor.
Vaginas stretch, this is a fact. They also STRETCH BACK. You can go back to having pleasurable single partner sex within 2 minutes of DVP. Or at least I can, and so can everyone else I've ever spoken to about this. Don't worry. Vaginas in an aroused state are very flexible and happy.
This scenario works with 2 guys, 1girl. GuyA, GuyB and Girl.
GuyA lays on his back with a happy boner. Girl gets on top of GuyA, facing him and slowly leans forward until they are belly to belly. It generally helps if GuyA has a long enough dick to allow this to happen, but really there doesn't need to be a whole lot of length to make this work. GuyA has his legs together. Pro tip: Pull out your balls so you don't squish them between your thighs.
You might want GuyB to lube up a bit, even if you get really wet, I'd suggest a bit of extra lube. It makes everyone happy.
GuyB, has his legs outside to GuyA's legs. This gives him the position and angle necessary to thrust without a whole lot of work (GuyA should already be inside Girl). GuyB is the one doing most of the work in this scenario. GuyA and Girl aren't doing a whole lot of thrusting. Girl has her knees outside GuyB's knees. It might take a bit to get used to, readjust as necessary. GuyB (doggy stylish, behind Girl) slides his dick in beside GuyA's dick. Go slow, if you're both thick give Girl a chance to get adjusted and allow her vagina to get used to the...hmm..influx of activity. Once everyone is ready, GuyB thrusts
There may be some slippage, just pull out, line up and go again. It's fun and easy!
Safety Tip This is not a scenario that is safe if both men are wearing condoms. It is very important for at least one of the men to not be wearing a condom. If your play style does not allow this, Try a female condom, but the men will still be touching. Two male condoms together will rub and cause friction, this could cause breaking or slipping. I have NEVER had a problem with just a single guy in a DVP situation wearing a condom. No breaking, no slippage.