Akito's blackmail

At the beginning of Kodomo no Omocha, Sana's classroom is a total mess because of the boys wreaking havok. Unfortunatly Sana's teacher Michiya sensei isn't very strong willed, constantly breaks down, and ends up calling for help from Tanaka sensei. Yet neither of them can do anything to stop him. This is because Akito managed to take a picture of them making out one day (which would surely get both of them fired if the picture got out). While Akito eventually comes to regret what he did, and Sana destroys the pictures, the photo's still manage to haunt Michiya and Tanaka even after their first ordeal.