He's kinda cool so I've actually talked to him about it. Says he can't stand the thought of someone else smelling his shit and it makes him feel embarrassed. And that he felt the same way as a child and by the time he was in highschool he never shit in a public restroom again.

I didn't say it...but I suspected perhaps he was given a complex by his guardians during potty-training. Like a method of punishment or shame that some idiots use on their kids.