Hmm. Is this how you get a pet? This might be how you get a pet!

He pets it gently as it drinks, and will refill the cap as many times as needed until it's done. "Can I take you home with me?" If it belongs to somebody else, he needs to return it, but how would he even know where to start looking? "Maybe just until we figure out where you belong. That'd be okay, right?"

This is definitely how you get a pet.