I wanna say it's an old movie. Maybe late 80s. I saw it a few years ago once. I'm assuming it's sci-fi horror; I'm pretty sure it's about aliens/parasites.
There's a scene with a man in bed, and he's talking to a parasite in his stomach. It moves, and he tries to calm/control it. I know at one point he says "Atta boy" but that's all I can muster up.
There was another scene where a girl was in the bathroom too, I’m pretty sure.