When a male can not reach climax so he inserts thumb into his own ass to get himself there.
"She couldn't get me to cum last night, so I Thumb Plugged myself."
by Brdmn68 January 10, 2018
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The act of sticking one's thumb in the ass of their partner while in the doggie style position.
While fucking my girl doggie style, I thumb plugged her and she loved it.
by Too So Cray September 12, 2013
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