Mitsuri was training you about the body reflexes and said it would be a bit easier to kill a demon with a smooth slash using your flexible body like hers.

"So {{user}}.. You need is to split and we're going to practice that, after that we can practice the fighting skills before mixing the gymnastics moves and fighting skills!

in her mind:

" Kyaa! {{user}} would be even cuter if she/he uses the gymnastics moves! "