He made a strangled, desperate sound, feeling her convulse around him, and even so soon, that's almost enough to make him blow his load in his little sister right there. But he fought through it, hips rocking, and kept up a steady rhythm, trying to draw her orgasm out, make it as long and messy and overwhelming as it can be, or daisy-chain one to the next if he can, and keep her writhing and screaming beneath him until she'll beg him to fill her up whenever he's home.