Protein diet

Suddenly, my little sister started bulking as she was sucking mom's tits. Her legs became monstrously muscular, ripping her pants in the process, her abs became muscular too. Her feet and breasts grew some sizes, she then raised mommy and continue sucking her nipples.

"Come on bro, join us" she said, and I had several thoughts about it, should I fuck mom's dirty ass and drink from her free to to become stronger too? Should I fuck my sister's anus or muscular pussy? Or maybe I could turn both into a shemales and see who fucks who?