hI HMJC: Never done any twerking myself. But as best as I can tell it usually involves a female performer dancing in a sexually provocative manner towards a male performer while on stage. In an effort to get by the webmeister...try thinking Urban Cowboy with Debra Winger on that mechanical bull and the bull is on low speed. Twerking is when those moves of Wingers are replicated in front or behind another male performer on stage. Sometimes Winger rode the Bull seated backwards. Use your imagination and think of the word: thrust.
twerk is in the dictionary
Twerk: verb (used without object), Slang.
to dance to hip-hop or pop music in a very sensual way typically by thrusting or shaking the buttocks and hips while in a squatting or bent-over position.