Cocks Easily Slide Out
There's no easy way around this one: at least one of the guys should have at least average long cock, preferably even longer. When you do a DP, put the guy with the longer cock underneath. This will allow the guy with shorter cock to adjust and push in from behind when doing cowgirl. If you're doing reverse cowgirl, still put the guy with longer cock underneath (he'll go into her ass then, but the point is that by virtue of being underneath he can't move as easily).Positioning
For DP, the easiest position is cowgirl: one guy in the bottom (preferably the one with longer cock, see above), girl climbs on top of him (facing him), second guy insert into her ass from behind/above. It's a little hard for the second guy to get angles right, so here's what the other two can do to help:
- Bottom guy grabs her butt cheeks, and separates them, exposing her anus. This makes it easier for second guy to insert his cock into her ass.
- Girl leans upper body forward as much as possible (lying flat on top of bottom guy), and pushes up ass. Just like during anal doggy style.
- Obviously, second guy that comes in from the back should use tons of lube (both on his condom and put lube around and inside her ass using his finger).
For DPP, I actually find reverse cowgirl easier than cowgirl. The reason is angle: the second cock (the one that would go into her ass were it a DP) can't enter the pussy a high angle, as would be the case when doing a DP in cowgirl position. When doing reverse cowgirl, the girl mounts one guy with her back towards him (the easiest way to start this position is spooning, then the guy simply rolls up the girl on top of him). Then the second guy enters missionary style (with lots of lube again). The only difficulty is all the legs: bottom guy and girl need to spread legs wide apart, so that second guy gets space. An alternative to have bottom guy with straight legs, and second guy "sitting" on top of his legs. Girl must obviously still spread her legs.
Girl may experienced pain
The way to avoid pain is to use a lot of lube and patience. Lube her holes, then lube both cocks. Second guy must enter slowly, both when doing DP and DPP. She must be really horny obviously, as this creates natural lubrication. Don't move too much in the beginning, let her get used to just having two cocks inside for half a minute or so. Then start moving very slowly, first only second guy (not bottom), as it minimizes the risk of cocks sliding out (see above).