Ore no Natsuyasumi 2

During your summer vacation your mother has asked that you take care of the two daughters of a friend Marina and Rie. She tells you they're 1st and 2nd grade students so you get very excited expecting two first and second grade high school girls. When you meet them at the station you discover that they are in fact 2 grade school girls! After their first day at your home Rie asks what a pussy is then asks you what sex is. She and her sister discovered your erotic manga. They now demand that you teach them about sex and how to feel good! How will your summer vacation end?