I do the same to mine in a large tub. He has one every other day he loves it he swims around then has a poo and gets out ;o) He now even dries himself on a towel! REALLY!!!
You can bathe a beardie in luke warm water up to their armpits for 20 mins this keeps them hydrated. Everyone does this diffrently I give all my beardies baths everyday time frames are diffrent. Babys get them everyday for 10 mins due to the higher basking temps. Older ones get 20 mins soaking time 3 days a week. We use a large clear rubermade container to give them their baths i hate having to scrub the tub and sink after every bath.
Oh and most important never leave them along while in the bath they can drown.