Short story schoolgirl suspects other girls is a witch

Question

Many years ago I remember reading a short story about (high?) schoolgirl who suspects someone from her school is witch/demon. I remember after the story escalates there is a confrontation between the two where the bad girl calls a slow witted demon downstairs. This scene is vivid in my memory because the good girl is small and the demon is overall huge and has an erection to match. I thought the title was something like “Twyla,” but I’ve never been able to find it.

I believe this is one of those stories I read in a science fiction anthology my father brought home on one of his business trips in the sixties or seventies. Since joining this site yesterday, I’ve had three other questions answered quickly and correctly, and this should be the last and most obscure for now.

Answer 1

This is the late Tom Reamy's short story Twilla. The main character is a schoolteacher in a rural area. The little girl's name is Twilla, the teacher is Miss Mahan, and the simple-minded Djinn with the one-track mind is Dazreel.

   “Dazreel is back upstairs,” Twilla assured her, watching her speculatively. “You have nothing to fear.” She smiled slightly. “He will have only virgins.”
   Miss Mahan felt the blood draining from her face and she weaved in the chair, feeling the panic creeping back. Twilla threw her head back and her crystal laugh was harsh and strident, like a chandelier tumbling down marble stairs.
   “Miss Mahan, you never cease to amaze me,” she gasped. “Imagine! And at your age, too.”