Na-i-sho is a 13 episode OAV series detailing the summer between the ~motto~ and the Dokkaan season. It is a bit more mature than the TV seasons, and looks to develop each of the five witches romantically. Hana is back to a baby, and the mahou shop is a bakery. (Source: ANN)
9Anime is the best site to watch
Magical DoReMi Na-i-sho SUB online, or you can even watch
Magical DoReMi Na-i-sho DUB in HD quality. You can also find
Toei Animation anime on 9Anime website.