Blot up as much urine as possible with clean paper towels or a dry cloth
Strip the bedding and wash it separately
Mix equal parts white vinegar and water in a spray bottle
Lightly spray the stained area
Blot again with a clean cloth
Sprinkle baking soda generously over the damp area
Let it sit until completely dry
Vacuum up the baking soda
If the stain remains, apply a small amount of hydrogen peroxide mixed with a little dish soap and baking soda
Let it sit briefly, then blot with a clean cloth
Repeat as needed
Allow the mattress to air-dry fully
Use a fan or open windows to speed drying
Place a waterproof mattress protector on the mattress after it is dry