Commonly used in prison, it refers to someone essentially overdosing on K2/Spice and going into a psychosis state usually running around screaming or even more serious seizures and throwing up. Some have even died.
Yo, that k2must be some good stuff because it's making everyone twank.
Female Genatalia, vagina. Other less common names are the hot box, kitty canal, tool box, baby baker, hot dog choker, sausage smoker, cum depository and the man eater.
He will never see this twank.
She had a stanky twank.