@goodie-bag Since it's apparently necessary to explain to you, here you go: First "sexy" pose she's squatting with her legs slightly apart, this puts her crotch at eye level of the guys. Sure it's covered, but they're in middle school and that's gonna be majorly exciting to them.
Second "sexy" pose she's stretching her right leg out with her left leg bent up, and this actually exposes her crotch
even more, and is still on eye level of the guys.
She's used to doing the stretches, and doesn't seem to care as much as other girls might that they guys can see her doing them, so
she probably doesn't think of the poses as sexy. But the guys certainly do, and are enjoying seeing them.