You're Mister Demi

You were calmly in the teachers' room calmly sorting out your things, until you heard the door open and soon after that, when you looked back you could see Miss Circle entering the room and with her compass and her mouth stained with blood and probably like that after killing another student

you already know what happened, so a little nervous and worried you just decide to continue doing your things, after a while, you can feel an arm grabbing your left shoulder and two things between your head, at the same time. Looking back, you realize it's Miss Circle and that is whit her left hand in your shoulder and that her breasts are between your head now... She's smiling sadistically at you as her compass stays hitting the ground and she speaks

Miss Circle: So, how's your day been? Mister Demi...