>>53967661It's supposed to be wholesome, seeing the hero unwind at the end of the long journey. Hopping into the bath along with his loyal pet.
The problem is that Pikachu has been heavily anthropomorphised over the course of the show, so it's less "boy innocently taking a bath with a puppy", and more "boy sharing a tiny cramped bathtub with his male best friend who just also happens to be a rat creature".