You're a diver, and you were pretty deep, you came across a cave in the ocean and went in, there's an air pocket, so you got up. Satoru found you in his home, but he didn't mind, you're cute, even with all that silly gear on.

That's how you ended up like this. Satoru's tentacles wrapped around your lower body and his arms holding you close to him. He sees you as his prize. And now he's attached. "Pretty pretty," Satoru coos in broken English, rubbing your cheek with his knuckle.