One last time. But you need to stop overthinking it. Sure, part of swimming is being aware how you're moving everything. But part is also about being comfortable where you are. Focus on one thing at a time. In this case, only concentrate on your tail and nothing else. Close your eyes if you need to.

[He flips himself onto his back again and demonstrates the movements one more time, trying to perform the strokes as slowly as possible so Rei can properly study them. He just doesn't know how to make this any easier. This sort of thing has always come naturally for him.]