[Pal Maison] Let's use a Penis Enlargement Pump with Onii-chan [Futackerman]

Manami talks her little brother into testing a penis enlargement pump, cooing over his modest endowment as the cylinder sucks him visibly bigger — only to reveal her own massive girlcock barely fits the device even while still soft. The silly experiment turns rough when the busty sister pins him face-down and forces her thick, veiny shaft deep into his ass, promising to pay him back in hot cum. By the final page he's a sweat-slick, cum-bloated wreck while Manami cheerfully announces nine more loads are coming, each priced like vending-machine stock.