The sexual act of 3 guys forcing a female to service them at the same time. While one guy sticks it in her mouth, the other two have her jerk them off into her both of her ear holes. All 3 men finish by ejaculating at the same time so that the female's ability to see and hear are inhibited, much like a flashbang.
Person 1-Did you see Jessica last night? That hoe was stumblin around like a damn drunk. It was like she couldn't see or hear anything, like fuckin Hellen Keller!
Person 2-Yea dude, she got flashbanged by a couple of freshmen.