When a man is engaging in cunnilingus with a woman and she defecates, he wipes and then continues. Referring to the manner in which one brushes aside a parsley garnish in order to continue enjoying the flavor of the dish.
Can refer to the man's act of continuing cunnilingus, or the woman's act of defecating mid-cunnilingus.
Dude 2: "Yo, that's nasty, homes."
Chick 1: "Oh my god, so I went home with that guy from the bar last night, and he went down on me, and I did a parsley! Soooo embarrassed."
Chick 2: "Um, yeah honey, next time try one less jager-bomb."
D: Yeah, but the guest list is too exciting. We need to throw some parsley in there.