Your girlfriend borrowed your laptop and found your femdom clip library while you were out. This is what you’re really into deep down? Jerk off instructions and CBT? The fact that you’ve hidden this from Her pisses Her off. She humiliates you for your kinks and takes Her anger out on you by making you jerk in front of Her with specific instructions. She’s going to be in complete control and you’ll never get to have sex with Her again.