This is possibly the most amazing yet terrifying sexual manuver in the history of mankind. The Double DP is a combination of double penetration and donkey punch. The standard double penetration is carried out as normal, until the moment just before climax when both males punch their female partner in the head at the same time.
This would probably be considered sexual assault and would technically be illegal in most states. Be prepared for the consequences (most likely a kick in the tesaticles)... or run away while she's unconcious.
Sly Rick: Yo, me an' Dirty Dan were takin' on this chick, we had her locked in from both ends.
Dirty Dan: Hell yeah, then we busted the Double DP. Boom!