Radiator Drain Plug

[trashmanpenn]

So I was draining the coolant out so I could replace some of the cooling components, and as I was unscrewing the drain plug and all hell was breaking loose, it decided it didn't want to come out. Now my garage is drenched with coolant. Anyways, every time the plastic plug is on the verge of coming out, it "clicks" right back into place, and it does this over and over again. Any ideas? Thanks.