When your banging your partner and then soon you start shoving your penis into her anus, and you try to shove it until it touches her sphincter, and then after minutes of shoving, you cum a painful stream into her anus. Named after the aerial stunt from MLP: FiM.
Last night, dude, I started giving your mother the sonic rainboom and she was like, "OWWW!!! STOP IT!!!!".