![Q and janeway in a bathtub](https://cdn.statically.io/img/static.wikia.nocookie.net/memoryalpha/images/0/0d/Q_and_janeway_in_a_bathtub.jpg/revision/latest/scale-to-width-down/180?cb=20070128163534&path-prefix=en)
Bathing was the act of self-cleaning and maintaining one's personal hygiene, that often had relaxing effects. For humanoids, this was often done in a bath tub or shower, using water; or in a sonic shower. (TOS: "The Naked Time", Star Trek: The Motion Picture, VOY: "Caretaker")
Some cultures used mud baths or protein baths as a method of relaxing. (TNG: "Birthright, Part I", "Cost Of Living", DS9: "Who Mourns for Morn?")
Bathing could take place in a bathroom, or a specialized establishment such as the Hoobishan Baths on Trill. (DS9: )