The drain spigot works with simple rubber washers.
For opening: half a turn is all that is needed to open the drain spigot. Over turning it can cause it to become unthreaded, and possibly remain in the ‘open’ position. If your spigot is draining by itself, then this is likely the scenario. Simply push in on the spigot handle while tightening, and the thread should re-engage itself properly.
For closing: A simple and light finger tighten is all that is needed to seal the bin. Over tightening can cause the inside washer to ‘roll off’ the sealing thread. By removing and disassembling the spigot, you can fairly easily reposition the washer if it has rolled off.
And as a reminder, all that is needed is a light half turn open and close with the spigot in the future and it should perform just fine.