When your thumb gets sore from holding down the throttle on a quad.
(after a whole afternoon of riding on the quad)
"Damn, I got throttle thumb!"
When a person jams their finger in their butt hole to prevent diarrhea from spilling into their pants
-Dude, is that guy scratching his ass in class?
-Naw man, that guy's doing a Thumb Plumb
Texting on two mobile devices while holding one in each hand
"I saw this crazy girl at the club last night. I was going to go talk to her, but she was busy double thumbing at the bar."
A name given to somebody who repeatedly texts or sends e-mails whilst taking a crap.
Joe: Where's Bill?
Jon: He's taking a dump
Joe: What a potty thumbs, he was just texting me
Jon: Gross!
Dickhead brothers (most commonly found in groups of 3) that resemble living breathing thumbs with shark characteristics. This is a rare species of thumb sharks can most commonly be found living right on the coast of Southern California near Redondo Beach
Girl 1: Those three boys just ruined our movie night
Girl 2: What a bunch of thumb sharks
Cold thumb is Ignoring someone's text message/not typing back/not replying to someone's text.
Keisha: Guapo, when can I come over?
Guapo: …(never responds)
Keisha: I asked you a question, why are you giving me a cold thumb…
the red and/or peeling skin on the finger, usually thumb, of someone who is new to smoking and/or smokes often because they are inexperienced and the lighter flame touches their thumb or finger
Hey man, what's wrong with your thumb?
Oh, I just started smoking, and now I got a smoker's thumb.
Here, let me show you how to use a lighter!