Thumb Plug
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."
Thumb Plug
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.
Kentucky thumb plug
Just put a thumb in it
“Hey bae can I Kentucky thumb plug your anus?”