Similar to an oops, but much better.
When your fucking a girl, and you secretly RAM it in her ass as hard as you can. Then without any pause, you start fucking the living shit out of her ass as hard as humanly possible. This will send her into INSTANT shock. When she finally regains consciousness and musters up a small amount of energy to say "what are you doing??", you start pounding even HARDER and yell out at the top of your lungs "OOPS!"

When you eat dirt for the first time and leave your family to build a shack in the woods