They DON'T need baths unless they are dirty, if they track in their poop --
bath. Otherwise unless they actually drink in the
bath there is no reason to put them through it. Contrary to popular myth they DO NOT
hydrate through their skin or vent. That is one of the absolute worse pieces of misinformation floating around. I cringe to think how many beardies get dehydrated because of it. They have to drink water or eat food high in water content to stay
hydrated.
Like Karrieree said, you can use an eyedropper to drip it on their snout. Your beardie should start lapping it up. If not you can add in a little none citrus fruit juice or punch to give it flavor. Be sure to use a wet paper towel or wet wash cloth to wipe away any that runs down their chin. No need to take a chance on causing bacteria or fungus to start in their scales. For babies they need water way more often than older beardies, they can dehydrate very quickly.