Why not just ban her from substituting?

Why not just scream IDIOT at her?

and store there called The Mercantile.

Or did she have a hairy crack-up?

Once there was a donkey at an assembly promoting a local fair and it got a huuuuge stiffy. The elementary school kids were too young to appreciate the comedy or understand why the teachers were in stitches. Personally I had little hands from boys and girls going up my legs all the time. At first I was surprised but got used to it when I realized that 6 year olds are very tactile and wanted to "feel my soft legs" when they sat on the floor around my teacher chair. They weren't accustomed to black tights and they were fascinated.

Or if there isn't, maybe there should be, like Zoloft or the like.

Who goes commando in a skirt?

for centuries. Doing it in a public school marks the beginning of the end of civilization as we know it. She must have got the idea from Ol' Man Willie on the Simpsons.

...under a kilt would be absolute torture.

A handsome guy in a kilt is the ultimate in sexy, IMO, especially if tall and slender with broad shoulders.