I knew I was supposed to be doing my homework, but I decided to watch porn and jack off to that instead. I got a zero on my assignment, and I feel like such a big failure.
Do you live with other people? If so, keep your door open or move your computer into the other room. Don't be alone because isolation triggers PMO behavior. Is there a place you can go to study in-public, like a library or cafe? If so, sit in the middle of the room and make sure your screen is visible to others.