The act of pouring bubble bath, bath salts, or dish soap in the toilet prior to passing a bowel movement. Many people enjoy listening to sounds of nature records while performing a shit bath.
Kelly: "I feel like I have been neglecting my mud muffins lately. My poop has been nothing but good to me and I haven't done a single nice thing back. I'm going to treat the next one to a nice shit bath."
Dad: "Don't use the good laundry detergent."