You don't need to have Fiera's Ring equipped to go through the Dragon Nursery, you can do it in the dark, using bonking as a guide to tell you where you are. Here are maps of a path you can take. As you get more familiar with the level, you'll be able to cut some additional corners :]

Note that even though you don't need to equip Fiera's Ring, you still need to obtain it! If you do not have the ring, you will not be able to free Fiera and your journey through the dark will be for nothing.

Because the bonk-path is less direct and longer than the path you'd normally take, this method only saves a small amount of time, even if you take into account the time it takes to swap rings to and from Fiera's Ring. But hey, a time save is a time save, and it's not so bad to learn if you start with having the map open while you do it.

Path towards the lamp: The green arrows indicate diagonals. If you're not comfortable with them, you can replace them with the appropriate horizontal/vertical paths, there are reliable bonk tells for all of them. The blue arrows indicate a slightly riskier path, risky in that after the second part, it can be hard to reliably know if you've bonked.

Path back out: The "good luck" bit is getting into that pipe, as there's nothing to line up for it. Since you only need to move over a little bit though, it's something you can get the hang of fairly quickly.

The flame wall at the top is a good indicator of when you've gone too far up, and is safe other than that, there's nowhere to get stuck up there.