During sex, when a man and a woman share a double sided dildo, thus simultaneously penetrating the anus of both individuals during vaginal intercourse.
I had a Buck Double last night. It wasn't at all what I expected, and I can't believe they actually advertise it in public.
by Leroy M. Jankins April 08, 2011
Getting pounded so deep that the testicles enter the anus
"Dude, Greg was deeper than deep, he was so deep that he gave her the Buck Double"
by Trent89 May 08, 2010
When you fart into someone else's anus or buttox
We got into some kinky stuff last night, we even buckdoubled
by Brain129 July 19, 2010