Your mom knows about your porn habits and confronts you. You can't hide them from her any more. She thought she taught you to be a good Christian boy and not touch yourself but evidently it didn't work. Do you remember when she found those cigarettes and made you smoke the entire box in front of her to rid you of the habit? The same is going to happen here. You'll jerk off for her until she's told you it's enough. It doesn't matter if you cum or not, you'll keep going until it doesn't feel good any more. Mommy knows what's best for you. Involves some pervert humiliation talk and strict religious mother themes.