Considering that a suppressor works by dispersing the gases (just like a car muffler), I don’t see why it would work differently on the first shot.

don’t suppressors not work for the first shit?

I can’t say. I’ve never fired mine from the toilet.

To answer the actual question yes, suppressors work for your first shot.

suppressors don’t make your gun quiet as much as they make them slightly less noisy, which helps if you don’t wanna blow out your eardrums. the legality of them varies tho