Sulu's eyebrows raise, and he leans, just enough to nudge Kirk off balance. This was skirting the line of professionalism, he's just about certain it is, but the situation calls for levity.

"I'm kidding, Kirk."

Maybe he was. Sulu didn't count leaving out crazy acrobatics as taking it easy, so it's the truth, as far as he's concerned. Fencing wasn't really about aerial manuevers anyway, not in the purest sense of the matter.