Old Trunks remembers butter on the burn. Maybe the butter dish was handier than the water faucet. Maybe they didn't have a water faucet.
The real truth about putting butter or anything greasy such as lotion on a burn is not the thing to do. The lotion, butter, or other greasy substances actually hold in the heat, causing the burn to become worse.
A cool cloth or even running cool water over a burn will reduce the heat and may even minimize the damage to the skin.