How do I get the mouth of the fountain to open?

Hint 1 of 8:

The candles are the trick here in both the king's and queen's chambers.

Hint 2 of 8:

You'll need to light the candles (or put them out, depending on the room) in
a certain order.

Hint 3 of 8:

Those candles aren't going to light (go out) on their own -- you'll need a
powerful inventory item to help you here.