First: Bed sheet
Second: Pet pee pads
This is very convenient, you can also use it do their daily use. Every pet owner should have this one.
I brought this on amazon from a seller named Adoric, this waterproof mattress cover really works so that my mattress is finally getting clean.
If you also get pets at home and have the same problem with me. You can have a try, if you got better idea, share it with me ;)