It should be a no-brainer to give Water Type pokemon some water right? Even for the ones that can survive outside water, they all still love to swim! Gotta make sure the babs among them are still padded up though.

If you do pad them though, they don't like swim diapers. Sure regular diaps get sloshy, but to them there's nothing comfier! Besides, it's just water!
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I wanted to have some fun with the pose here. Oshawott's an interesting pokemon in terms of design; kinda looks weird if you mess it up. And for specifically diapers you gotta give it some legs!

(Day 22: Fire Starter)