Our first I used a glass baking dish with a towel since he didn't move much. This one I do in the tub (our sink isn't big enough even though he's small - just the shape of it I guess), since he is more active and more likely to run right out of the dish. He does do a little "glass dancing" on the side of the tub at first, then figures out it's
bath time and settles onto the towel and relaxes. I think it depends on the personality of your dragon. The tub is easy though. I fill with warm water just enough to cover the bottom of the tub - that makes it shallow at one end, and up to his shoulders at the other. I place the towel in the middle area and get it wet and "sink" it so it's on the bottm as best as possible. Once done, I take him out and place him on his basking rock to dry off and warm up, then I drain the tub and spritz with bleach. Simple. While he's in the tub I just sit next to the tub where I can see him and play a few rounds of skee-ball on my phone. Before we know it, the 15-20 minutes is up.
Whichever you do (tub, sink or dish), just be sure you are there watching. It's like having a toddler in the
bath. You don't walk away ever and you keep your eye on them at all times
Here is a recent pic of Pagona Bob using his towel pillow ....