The art of sheebing someone is being able to make fun of them, to their face without them realizing it. Named after a lame-ass Ultimate Frisbee player at Towson University, this challenging and rewarding art of mockery is constantly used (to his face). In responce to the said persons obliviousness, it was dubbed "the art of Sheebing".
She's just sheebing you man!
You've just been sheebed, idiot!