I’m pretty certain I found this on DeviantArt though I may be wrong.
Premise: a guy joins an early education class that is very select (~6 people) the teacher, Miss Amy, comes in with a machine that produces gas that regresses them to 2 year olds and may regress them more.
Any help with the name would be appreciated. BTW check out The Daycare Coven I just discovered it yesterday 7/10