LMMFAO

Maybe you were to quiet? o.o

Keep masturbating while he says stop, and **** him when he comes in to show dominance.

Yell "NO!" In response and go all out.

I'd most likely explode from frustration. Everyone needs their fap time.

Dude, that really sounds like theres a hidden camera somewhere, or he's found a way to intercept your laptop/computer webcam. My dad did something similar but it was a screen capturer software he used to spy on everything I did and come into my room to interrupt me if he saw anything slightly 'inappropriate'. Well now he actually can't legally use a computer or internet enabled devices now so I'm free! Find somewhere else to do it, maybe the bathroom or during your shower. Look at stuff on your smartphone if you've been using your computer. And sorry your dads such a dick, OP :(

Check for cameras

LOOK FOR CAMERAS!

Umm… maybe try when nobody is home? Idk, this is weird.

There's a camera. There has to be a camera. Unless your walls are paper thin and you weren't being very quiet, that is.