Your mother is clearly upset about something, when you get home she has that look. You stare and wait for her to express whats on her mind, and she starts venting nonstop about your sex life. How finding out you were fucking your sister was hard enough and now that your cousin is staying with you guys for a week or so, she found out your fucking her to. Shes even more pissed that she went out of her way to get your sister on birth control so you wouldn't knock her up and now your risking impregnating your cousin! Shes not on birth control and demands you stop fucking her until she gets her on the pill. You tell her shes just jealous. She denies this accusation of course and lectures you further, but you when continue to push the jealousy issue and she starts showing signs of interest you take advantage of the moment and pull out your cock. She tries to resist but can't help herself. Maybe she is jealous, maybe you should be fucking her, its not like you can get your pregnant mother pregnant again. After all with all the hormones flushing through her lately she deserves this... you both do.