tailboning 

A sexual act comprising of a woman (without a penis or any protruding penis-like object in the genital region) thrusting her hips vigorously upon a male's tailbone so as to achieve orgasm through clitoral stimulation. Tailboning is a common pastime amongst nymphomaniacs and sexual deviants alike. Often a quick, random action, tailboners get some of the best orgasms known to man and to the Pagan gods.

Music to tailbone to: Fela Kuti, Death Grips, Charles Mingus

I was laying down and she was on top of me trying to fuck my ass with no dick. My tail bone wrecked that clit and she orgasmed for days. Tailboning gets me all the concubines.

tailboning by Fiskeleton October 15, 2015

Tailbonitis 

Condition associated with long term exposure to commercial flying in coach class when your tail bone hurts like crazy after 2 hours in the seat.

Son in seat 150C:
Hey Dad, why is that guy in 148D sitting like he has crapped his pants?
Dad:
Don't worry Son, he looks like he travels a lot and has tailbonitis. He is just trying to take the weight off his ass bone, so should be safe to go near.
Why don't you be a sport and give him our pillows?

Tailbonitis by coach class traveller March 18, 2017

tailboning 

The act of having sex with someone using your tail in place of or in unison with a penis.

furry 1:Hey man did you see that new yiff flash from zone-tan?
furry 2:Hell yeah!They were tailboning hardcore!

tailboning by Passing June 24, 2014