The act of ejaculating in a chicks butt, dipping your index finger in and having a good swirl (best done left handed). After mixing in the bung hole for a while, you remove your finger now basted in the semen entrenched fecal potion. This is done doggie style so the chick is clueless when you reach around and stick your index finger in her mouth and give her a good Polish tooth whitening. Finish off by wiping your dick on her curtains.
When money is tight or you are too cheap to by generic whitening strips, it's always prudent to give your girlfriend with discolored teeth a good old fashion Polish Tooth Whitening the next time she gets a rogering from behind.