Taking a shower where the water temperature is luke warm or tepid. Caused by heavy demand of water heater's supply of hot water through heavy hot water use--other people taking showers or baths, laundry or dishwasher, etc. The temperature of the water is far from invigorating or comfortable. The water is barely warm, just like horse piss.
Hal: Are you expecting alot of company for Thanksgiving vacation?
Frank: Yes, my son, his college roommate, my in-laws, aunt, uncle and cousins will all be at my house. I'll have to make sure I'm the first one in the shower, otherwise I'll have to take a horse piss shower.