Dragons generally do not need a
bath unless they are soiled, soaking an injury, or need assistance "passing food."
There are some dragons that do enjoy just soaking and some enjoy swimming, but as a desert dweller they don't have a need for a
bath and could cause more harm than good, i.e respiratory issues and stress. If your dragon does not enjoy them, don't force them, as they are not necessary.
My oldest enjoys soaking, so I will run the sink water on warm, not too hot, to about her chest level and gently set her in. She'll sometimes want a drink while there, so I'll drip
bath water onto her mouth for her to lick up. She will soak for about 10-20 minutes before showing signs of wanting out.
My youngest hates baths, but I offer them in cases where I know he needs to poop and does not want to soil his vivarium. Same method, warm, chest level water. As soon as he starts to go, I drain the water, remove him after the deed is done, clean up the mess, towel pat him dry, put him back in his basking light, and go back to bleach/clean the sink thoroughly. I do not keep him in any longer than necessary as he does not enjoy soaking.