The product of having extreme hardcore anal sex with someone who has to take a shit. The feces are left mushy and loose often seeping from the anus in a soft milkshake-like form.
Miranda: Are you ok? You're walking a little funny.
Jennifer: Yeah. Billy Bob gave me an ass milkshake last night.
Miranda: OH SHIT!!
Jennifer: Yeah. Billy Bob gave me an ass milkshake last night.
Miranda: OH SHIT!!
by Dr. Purple Cock February 5, 2014
when you put a bottle of milk up a girls butt, and she shakes what her mama gave her. take the bottle out and there you have it a nice bottle of ass milkshake.
by hellxhope May 28, 2014