On the eve of Nightmare Night, Rainbow Dash is finally poised to enact her dastardly, clever and awesome plan. The goal? To scare Pinkie Pie right into her embrace so she can admit that she fancies her.

Saying things do not go according to plan is probably redundant.

Mood Wings - Observations on Pegasus Body Language.

When Twilight Sparkle finds this book, she discovers an entirely new field of research. The secrets of pegasus wings lie before her, and she insists on making her own observations on the matter.

How?

Field research, of course.