The little moments before and after Fluttershy was made up to be a clone of Rainbow Dash during "Magic Duel". With their futures at stake, Fluttershy knows that she herself has to try hard as well to pull off their trick in order for it to work. The little boosts that come in the form of Rainbow's love and confidence in her are usually part of what she needs.
Warning, pure fluff.
Co-written with Flutterdash7, rated for suggestive dialogue.