The former Indiana teacher charged with sexually abusing multiple underage children while they wore “Scream” masks has a big adjustment to make behind bars … no more sex!!!

Brittany Fortinberry is being held at the Morgan County Jail in Martinsville, IN and there’s no way she’s doing the nasty … because there are no conjugal visits, no access to porn, and no sexually explicit material — and she’s all alone in her cell.

A rep for the jail tells us Fortinberry is in general population and she has a cell all to herself, despite each room allowing for 3 inmates. It’s just her and a metal bunk, sink fixture, towel hooks, toilet, mirror and a night light.

Fortinberry’s day-to-day is pretty boring … in the mornings, the doors to the cells are opened and she can mill about with other inmates or hang in her room. There’s a TV with cable in the dayroom, where live basketball games are the biggest hit.

She gets three meals a day, but she eats alone in her cell … with jail staff coming by to slip her a food tray through a slot.

The jail menu typically includes cereal, fruit, cake and a pastry for breakfast; spaghetti, pudding, vegetables, rolls, cake and hot dogs for lunch; and chicken patties, bologna sandwiches, rolls, cake and fruit for dinner.

Sounds like Fortinberry’s been on her best behavior in jail … we’re told she has not been disciplined and correctional officers have not filed any reports of bad conduct.

Remember … Fortinberry is facing a slew of felony charges — 29 in all — for child molestation, contributing to the delinquency of a minor, dissemination of matter harmful to minors, and more. If convicted, she faces decades behind bars.