The act of giving or getting hit with a "Flyin' T" is someone who runs up out of nowhere with or without pants on, but having their penis out to jump into the air spinning with their arms out in "T" formation (thus the "T" in "flyin' T") and slapping, hitting, or srtiking their entended target in the face with their penis.
"dude! i was in the mood for a massive Flyin' T, so i just went for it! thank god the ceiling was so high! she was like 6'2!"