When someone has at least one abnormally long fingernail (usually the pinky) on each hand. Though it is not usually stated, it is assumed to be a substitution for a straw, rolled-up dollar bill, etc. for snorting cocaine.
Guy 1: Man, I wanna do some blow, but I'm outta straws and cash.
Guy 2: I got ya, scro! That's what my coke nails are for!