You shouldn't go into your parent's bedroom without their permission.
James was invited to go to his friends house for dinner tonight.
James wants to ask permission from his mom and dad.
James knocks on his parents door, and they tell him to wait until they come out, and when they do James asks if he can leave to his friends.
James walks into his parents room and asks if he can go, but catches them having sex.
James gets to see his friend and his mom and dad are glad that he had the sense to knock first.
James and his parents are all embarrassed, and he gets grounded for coming in without knocking.