thumbing it in slack 

When a man fails to achieve an erection but is undaunted and proceeds to push his penis into the vagina or more commonly anus and attempts sloppy sex by pushing in his penis with his thumb.

Nathan - Aww man im going to jail. imma be some guys bitch. i hope they are tender and start by thumbing it in slack

thumbing it in slack by SGTKM December 1, 2010

thumbing-the-gums 

A scholarly term for female masturbation.

"It doesn't matter that Brad didn't call because I'm busy thumbing-the-gums anyway."

thumbing-the-gums by Nora J. April 24, 2010

thumbing it

A reference to hitch-hiking, where one puts out one's thumb in the thumbs up position in the hopes that a passing driver will stop and give a ride. Used when one does more walking than riding.

The car rental place was closed so we ended up thumbing it most the way.

thumbing it by patdurling July 31, 2016

thumbing it

placing ones thumb in a females butthole while in the doggy-style position

i was thumbing this one broad from montebello

thumbing it by dick starbuck March 30, 2004

Thumbing the Sausage 

Verb - The act of rubbing yourself and thinking of hot women or ex-girlfriends during boring and drawn-out meetings.

"Wow, that meeting dragged on."
"Yeah, I know... I was thumbing the sausage for the last hour!"

Thumbing the Sausage by He who had the most fun June 25, 2008

Thumbing it in

Using your thumb to help pleasure a woman cause you can't get it up.

Mart had to much to drink and couldn’t get aroused. So he didn’t disappoint the lady he used his thumb to help get it up there (thumbing it in).

"Like trying to push a Marshmallow into a piggy bank."

"You’ve got it!"

Thumbing it in by scratch_nasty November 2, 2011

Thumbing A Saftey 

A Fife term, originally describing the practice of opening a soft roll, this has been corrupted to describe the sexual act of stuffing a flaccid penis up one’s fanny.

Generally only practiced by Fife Sengas in a desperate attempt to get some sexual pleasure from the ned they picked up only hours before.

"See me, ah wiz pure thumbing a saftey last night...useless prick."

Thumbing A Saftey by Bruce February 1, 2005