When one partakes in the act of inhaling cocaine through the nostril. The "hoover" section of the saying comes from the vacuum brand, while schneef is a variation on the word sniff or to sniff. "Schneef" is slang for cocaine.
When your man pubes are completely grown out, and you smack your bitch in the face with them. To your discontent, your pubes get caught on her snaffle tooth, sending your entire bush into her mouth