Tamako-san to Kashiwa-kun

is a Japanese light novel series written by Hitoma Iruma, with illustrations by Hidari. The series began publication on July 10, 2010 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Q: Do you like older sisters?

A: Yes, I love it. Tamako-san, who started dating two months ago, is an adult woman who is older but a junior student.

This work depicts the fascinating days of a card game study group with just two people playing an erotic game in a closed room with such a wonderful sister! (But that's really it)

Oops.

I would like to decline, but Tamako-san and I are by no means a crazy couple. Because it's a metamorphosis couple who plays a game of only two people. ...... Is that okay?