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The girl performing the handjob proceeds to hold the penis only showing the head and proceeds to hammer the head with her other hand angrily, like the thwomp in Super Mario Bros. Thwomp hammers are common after the one receiving what appears to be a bad handjob criticizes her technique, leading to the painful act and loss of manhood.
guy 1: "I was getting a handjob from this girl and I tried to give her pointers. I don't know why, but she punched my dick so hard why did she do that!?"

guy 2: "Dude, she gave you the thwomp hammer!"
by TheRoommate207 October 30, 2011
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