>>49665560I think it's something about how sheltered she is. With stuff like Yuyuko actively discouraging her from studying and refusing to be of any help in teaching her anything, the fact that she doesn't really know what break time and days off are, and the way she has a 'strike first, ask questions later' mentality going by PMiSS saying she starts attacking anyone coming to the netherworld before even checking who they are.
I think she'd have sex for the first time, get completely hooked on how good it feels, and since its something that isn't controlled by yuyuko, she'd want to do it every way she can, whenever she can.