Hmmmm.... this is one I have never heard of before.
There's a hack going viral that says you should be putting a clove of GARLIC in your toilet at night. According to House Digest, you just peel one clove, drop it in the bowl, and let it soak. You're supposed to do it twice a week.
Not everyone loves the scent of garlic, but it's supposed to help with lingering bathroom smells. You can also supposedly crush up a few cloves, make garlic tea, and dump that in there to help with yellow stains.
Some people think it's a waste of garlic though, and maybe you just need to clean your toilet more often!