(Verb) The unsavory practice of a man sticking his cock in both a woman's vagina and asshole without washing his cock in between orifices. Oftentimes is the case this dirty bird will alternate between the two without any consideration of the health hazards he is potentially placing on his receptor.
Shut-faced drunk Kevin was throwing the cock to Betsy with reckless abandon and throwing caution to the wind doin a little double dipping action as he slid his cock first in her asshole and then her vagina and continued to do so in no steady order. Being one if her many 'trusty-rusties' Betsy could tell whenever Kevin was about to cash in his chips, so when that came about she quickly pushed him out of her and proceeded to polish his knob so that she wouldn't seem so slimy to her current boyfriend if she had to go and put up with his shit later. Plus being a semen depository for so many sometimes gave Betsy a not-so-fresh feeling inside, and smelled pretty funky outside as well.
from Seinfeld:
"Did you just double-dip that chip?"
"Excuse me?"
"You double-dipped the chip."
"Double-dipped? What are you talking about?"
"You dipped the chip, you took a bite, and you dipped again."
"So?"
"That's like putting your whole mouth right in the dip. Look, from now on when you take a chip, just take one dip and end it."
The act of two males performing anal sex on a female, and then proceeding to place the tips of each of their fecal covered penises in a nostril. The males ejaculate blowing semen and feces up into her nose. The female then hocks a lugee of cum and poop, spitting it gently into an used chocolate rapper. This action is known as the belgian double dipper because the resulting viscous liquid looks like a white belgian, chocolate which was then dipped in dark chocolate.
double-dip verb
past tense: double-dipped
When the male participant in intercourse between a heterosexual couple inserts his penis into the vagina, then anus, then back into the vagina again. Advisory: can cause urinary tract infections for both partners.
Joe: aw man, shouldn't have double-dipped with my girl...
Steve: why?
Joe: both Suzie and I now have urinary tract infections
Double dipping is a generally frowned upon act where a person at a party with snacks dips a chip he/she has already taken a bite out of into the dip a second time.