What is Thumbing?
1.
Similar to fingering a girl, but done with the thumb
that babe'n'babe really liked it when I was thumbing her
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2.
Punishing your significant other by inserting your thumb in her ass without warning. A technique that is crude, but effective. See also, ad hoc.
Thumbing--She wouldn't get ready to leave, so I thumbed her so she would get out the door.
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3.
when one is too busy to be bothered with something he/she had already committed to doing, especially applicable when letting an entire group of people down
Instead of coming to D&D on time so everyone could start the game, Otto Normalverbraucher was busy thumbing his ass.
