A fetish sex act where one partner rapidly swirls his penis inside his partner'
s anus until finally ejaculating, at which point a cup is place beneath the anus and the cum (mixed with butt junk) that is inside is allowed to drip out of it and into the cup.* A straw is then placed in the cup and one or both partners drink from it. It is often used as a humiliation tactic with the man forcing the woman to drink the milkshake or simply throwing it in her face when she turns around to look at it.
*Note: There are varying "flavors" of milkshakes depending on how much
ass-
gunk is loosened up inside the
butt. These range from "
Vanilla" (no poop particles, white coloring), to "Milk Chocolate" (light
brown coloring), to "Dark Chocolate" (nearly black in color), and finally "Strawberry" (Done when a girl is on her period and doesn't want to take her
tampon out to have vaginal sex and instead offers butt sex. To make one you must first make a Vanilla Milkshake and then rip out her
tampon and stir it in. Best done as a surprise to the girl).