A series of OVA episodes released with the limited edition manga volumes.

Episode 01: What You Gave Me (Anata ga Watashi ni Kureta Mono)
Kokonoe, Usa, and Kagami go shopping for a present for Sensei. Eventually Kokonoe decides to make one and they all end up spending the night at her house. Along the way we learn more about Usa's love for Reiji, Kagami's love for Kokonoe, and Kokonoe's love for Sensei.

Episode 02: Kuro-chan, Shiro-chan (Kuro-chan to Shiro-chan)
Kuro-chan tries to become friends with Shirai-sensei.

Episode 03: A Child's Summer Time (Kodomo no Natsu Jikan)
The girls, Aoki and Houin go into the country to visit Aoki's family.

3rd grade teacher Aoki Daisuke didn't expect the first class he ever taught to be one of the toughest obstacles of his life. After getting off on the wrong foot with the entire class, a moment of kind-heartedness instantly convinces one of his students, Rin Kokonoe, to make the ill-fated Aoki-sensei her lover. But what exactly are Rin's intentions for wanting to actively seduce Aoki-sensei, and will Aoki-sensei be able to help her to deal with them?

The second season of Kodomo no Jikan.