When students are mischievous, a teacher often has to call them over for redirection.
In the best of cases, you're able to do this quietly so a child isn't "called out" or publicly redirected. Sometimes, however, given the situation with many children in one class that's impossible to avoid.
When you do call that child over, one great strategy is to start with a positive message such as, "Before I talk about the reason I called you over, and while I have you here, I wanted to compliment you on the __________________, and because you're so capable in that way and so many more ways, let's use this time productively. How can I help you stay on task and contribute, rather than interrupt others' learning at this time."
Typically when I do this, a child has the good resolve for the mischief, one I'm able to follow for a win-win solution.