When having sex with somebody from behind, the receiving partner reaches back with their right arm and forcibly attempts to jam their fist up the ass of the giving partner. Named after Thaal Sinestro, the arch nemesis of the Green Lantern, the name is a reference to the fact Sinestro wears his power ring on his left hand so his right hand is free to penetrate people anally, as most supervillains often do with their free hands.

When you eat dirt for the first time and leave your family to build a shack in the woods