The movements are very natural.
Why are you surprised by the water being cold? You already a leg in it, you goober.
This is a proof of concept in how I would be able to animate. There is a lot of room for improvement with how I create the animatable parts. I need to plan out how everything is going to move and make the assets based off of that.
Things I used (I think thats everything?)
https://animereferenceposes.com/anime-sexy-poses-reference/#sexygirl
The movements are very natural.