What would you do if you caught your son having sex?

[Gorilla Thrilla]

All throughout high school whenever i was trying to diddle my girlfriend, my mom would barge in and regardless of if I was clearly having a great time, stand there and yell at us to stop. It was honestly traumatic and she once did it when I was on the verge of ejaculating and I have never been more angry at her. I would think that the normal behavior would be to just talk to your kid beforehand and tell them to be safe, and then if you know they are banging just let them get it done.

Is this normal? I really don't think so but I'm curious.

As an aside, how would you handle the situation?