HUNTA-007 - Boyfriend is too bad at sex, so the big sister steps in to teach him

*This work is like a lecture where he can't stand the sloppiness of his sister and her boyfriend's sex. The 1st and 2nd pair were very good, but at the end, the high school girl also looked like an old lady, and she wasn't very good at playing the older sister role. I just can't do it properly if I'm taught it. If you can't do what I taught you, like the guy in 2, you're not a scumbag, you're just an idiot, so we need to make it so that people can say that you're good at it. Please be careful.