Ok so I never read the manga and decided to check this chapter. Didn't expect to find this relationship between the senseis. The manga has come a long way since the anime, huh.
@Gazz91 lots of jp couples still call their partners by their family names, and even married ones call each other with "-san" which I personally feel is not exactly very intimate. Guess it's just their reserved culture.
@JulesMFinWinnfield yeah because they already did that when they started going out (it's the very sole reason why they're going out, thanks to Kitou-sensei). Now we were shown explicit k i s s i n g, by preschoolers no less.