3 definitions by Thanks for the help Melp.
by Thanks for the help Melp. July 14, 2008
Rather than the thumbs up or thumbs down response to something, "thumbs in" denotes an inability to care less. While holding one thumb up and the other thumb down, you then bring both thumb gestures behind you and motion to place both thumbs "in" your ass.
by Thanks for the help Melp. March 12, 2015