Anyone But Him

Harry can't work out why his Amortentia for his seventh year Potions class makes his skin crawl every time he catches scent of it.
Severus cannot understand why the brewing of Amortentia for his N.E.W.T students has suddenly left him so irritable. The scent of it had never bothered him before, and he cannot work out why, now, it makes him want to curse everything in sight.
When they each in turn work out the reason why, neither want to believe it means what they think it means. However, one brazen move from Harry lands him in detention, and it's unlike any detention he's ever heretofore experienced...