Couldn't remember which website it was on (more than likely nhentai). The plot is about some adult female school staff (not sure if it's a counselor or teacher) who is also a futanari, has a fascination with the girls at the school. She tries to control her urges but she ends up drugging one girl and then fucking her while she is knocked out from the drug. The next day, she then moves onto committing the same act with the next girl, and the next, fucking her while she is asleep. She then admits in one of the sex scenes that she loves the feeling of the young girls. The tags would be futanari, lolicon, and probably rape too.