DVAJ-371 Living on the edge of incest without intercourse, only allowing insertion up to 3cm with little sister Aoi Suzuki

A brother who noticed the suspicious behavior of his younger sister Aoi. When he questioned him, he said he was practicing wearing rubber on her brother's cock. Since then, she decided to cooperate with Aoi's rubber practice, but... it's too painful to leave her erected, so she asks Aoi for ejaculation support. They couldn't endure just handjobs, and fellatio and even manjobs...Finally, they came to the point where they could barely insert it. . Before long, just inserting the glans wasn't enough, and they began to want to fuck each other all the way to the back of their vaginas.