Young sister practices on brothers dick and learns to suck

My slender, pretty sister has intimate problems and she comes to me for advice. It turns out her boyfriend accuses the girl of not knowing how to suck. Or rather, she knows how to suck, but she does it in a way that the guy doesn’t like. Well, yielding to Cutie’s intimate proposal, I agree to have sex with her in order to teach my sister how to have sex... Well, let her friend grow horns, if he’s such a goat!