Wizards are disgusted by sex and anything lewd. Witches have crazy libidos and are horny all the time, but have learned to hide it. Harry Potter isn't like other wizards, and so begins his new life of sex and debauchery.
A time travelling Harry Potter has been hired on as Hogwart's very first mental health counselor. Will his peculiar methods be effective in helping the many sexy witches that are sent his way? Probably, yeah.