The simultaneous use of the P90 submachine gun and rushing (the act of quickly attacking your enemey before they have a chance to prepare)
While it is mostly found in Counter-Strike Source this technique can be extrapolated into real-life situations with imaginary weapons and enemies. The objective is to reach your target while using imaginary flashbangs and smoke grenades. You are not allowed to be seen. If seen you fail the P90 rush. Enemies are commonly found to be parents, siblings or room-mates
Gamer1: I'm going for a P90 rush, wanna join me?
Gamer2: sure, I'll buy a few flashes
person1: Wanna P90 rush the kitchen for some hula hoops?
Person2: Yeah, I'm famished *loads imaginary P90* Alright, lets move out