1. Named after the reddish, foul color of the discharge from a woman's vagina during her menstrual cycle, it's the slang used to describe the course of action that occurs when one is so horny and filthy that they perform a sexual act with a woman (or transvestite) on their period, completely disregarding shame and health. Usually refers to the act of oral sex with a woman on her period. Is not thought of as cool or as something you would bragg to your friends about.
2. Period eating (usually accompanied by a bib or sponge).
1. (After looking at Johnny's face)
Gil: "You slob, you've eaten ribs three nights in a row, are you some kind of nigglet 'er somethin'!?"
Johnny: "Haha, of course not Gil, that's silly, I'm no nigglet! Ya see, Sue's on her cycle so I only got about two more days lef to red wing her." (dialogue taken from "Johnny Deeper--an American Poet")
2. Red winging has played a valuable role in history. Periods were thought of as a delicacy in Scandanavia during the Neolithic Period and is thought of by many historians as the origination of the red facial hair and pubic hair that haunts many Northwest Europeans today. (Columbia Encyclopedia)