Waxing: what’s the etiquette around erections?

Serious question. I’m getting a vasectomy so the whole area needs to be bare. Instead of doing it myself and risking ingrown hairs I want it professionally removed.

I’m sure unintended erections happen all the time. What’s the etiquette if it does come up?

Do we just ignore it?

Do I apologize?

Do I leave a bigger tip for the inconvenience?