Sniffing smudges on toilet seats

I have NO fucking clue why this happens and happens so often, but, if I happen to see a nasty ass brown smudge on a toilet seat that I am peeing into or something (public of course), in instant thought pops into my head of getting my nose right up to touching it and getting as close as possible. It's the grossest thing in the world and I really DO NOT wonder how it smells, so I have no idea why I have these thoughts or where they came from. And no, I am not into scat. lol