Place it right after the mistake is shown, then follow it with the sad violin for a dramatic apology beat, or cut to the oh my god wow reaction when the other person finally forgives you.
Über diesen Sound
This is a short spoken apology lasting about twelve seconds, in which a voice says sorry for doing something it did not mean to do. It feels sheepish and a little uncomfortable, like an apology offered quickly before the other person can answer. That awkward sincerity makes it easy to recognise and hard to take as a joke.