Blot up as much urine as possible with clean paper towels or a dry cloth
Remove 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 over the damp area
Let it sit until fully dry
Vacuum up the baking soda
If odor remains, apply an enzyme cleaner made for urine
Let the mattress air dry completely
Use a fan or open windows to speed drying
Repeat if needed
Use a waterproof mattress protector to prevent future stains