He used it... Episode 9

With a magic count of only three, the girls start thinking of ways to help Kazuki increase his magic count. Kuriko mentions a magical spa that is supposed to increase a person's magic count. As it turns out, the three girls and Kazuki must play and beat a baseball team from hell. If they win Kazuki gets one more magic attempt but if they lose they must go to baseball camp in hell for all eternity. Kazuki and the girls end up winning the game, but only after Kazuki had to resort to using his magic, so, while he did gain an extra use of magic from the game, it had gone to waste. His magic count remained at three by the end of the episode.