The little sister is cute but very lewd

This lucky guy gets his girlfriend to let him spend time in the house, eating and drinking all kinds of things. But unexpectedly, his lover's younger sister Riri Minase is a paranoid, lustful girl. Even though she was young and tiny, her sexual desires were extremely high, even soliciting her sister's lover for sex. With strong and persistent clinging like a leech, this girl finally manipulated this brother into having sex with her…… And then….