Bookending 

The act of two partners both anally penetrated using the same double ended dildo.

Both partners then rub against each other - back to back in order to create the visual of bookends.

"Me and my wife tried bookending last night! That double ended dildo was way too big for me! My ass is soooooo sore today but it's not that bad in comparison as she's still at home trying to fish it out.... Great night!"

Bookending by MrMeow147 April 22, 2017

bookending 

A form of homosexual foreplay where two men situate themselves naked on the floor in the shape of two 'L's with the backs of their legs together - representing two bookends from a birdseye view.
The touch of ball sacks is enough to drive those gays crazy and they are well on the road to brown loving.

"I saw this DVD called 'BookEnders'. They were bookending in it!"

"We bookended till the veins popped up"

bookending by Thomas Predicodd September 23, 2008

bookending 

To arrive at work before, and depart from work after, your lazy-ass coworkers.

Tom is very unhappy that he's been bookending his jackass boss Harry.

bookending by Jeff Hizzle January 14, 2008