thumb action 

another phrase for talking about playing video games (ps3, xbox, gameboy) They all use your thumbs

"Stop playing so much thumb action Billy", said Billy's mom

Eddie is really good at thumb action right?

thumb action by scottybballler23 April 5, 2010

Thumbation 

When couples are holding hands and then start touching or petting each others' thumbs. Can evolve into thumb wars and other kinky behaviors.

Man Friend: "So what did you do at the movies with Katie at the movies last night?"
Dude: "We held bands. Little thumbation."
Man Friend: "Kinky."

Thumbation by Dave Rowe January 27, 2009

Thumbactionist

1.) A boy or a girl who is an expert in sexting and finger talking.

2.) Someone who is extremely adept in using his or her thumb to have a full conversation on cell phone. These people are able to enjoy every action vicariously through cell phone chatting and text messaging. They hold the cell phone in such a way that their thumb (of the holding hand) can reach every button of the cell phone without any difficulty.

Jason can provide us upto date results of the NHL game through his blackberry sitting inside the rink. He is a thumbactionist !

Julia recently joined twitter and became a thumbactionist after meeting other single twitterers..

Thumbactionist by Shazz Spazz (Vancouver, BC) September 4, 2009