how to loosen coolant draincock

hey, i drive an 2003 sonoma.. and i'm looking at draining the coolant and i couldn't find anything on the drivers side like most of the other topics say where to find the draincock.... but did find a little plastic plug on the passenger side.. but it had angled sides. so you could close it by hand.. but couldn't open it.. also it looked like there was some sort of larger sized roberston that went into it to open it. i'll have another look for the one on the drivers side.. but if anyone has any comments about this. please post up.

Pull back on the " winged"plug you tried to open, counter clockwise about 1/2 turn, then pull it out.

well it seems the plug didn't want to be pulled out.. so i tryed to pry it out with a screwdriver and snapped off half of the "wedged part".. god i love gm.. why couldn't the just put a 10 mm bolt in there..