look up any word, like ebola-head:
 
1.
When you and your friend stick your thumbs up your own asses and then you grab a hold of each others fists and work them up and down. (Similar to a dutch rudder but with thumbs and asses instead of dicks)
Me: "Jem and I gave each other a Dutch Thumber yesterday."

X-Ray: "Is that gay?"

Vav: "Of course its not gay."
by The Thumbing Dutchman February 04, 2013