Succubus Yondara Gibo ga Kita!? EP2 - Episode 2

Since the day Takashi had summoned a succubus in a ritual, Eririn had begun to appear everywhere, even when she wasn't called. While she was studying and in the pool with her friends.

With each passing day Takashi saw Eririn as his stepmother Eri. One day while he is carefully observing his stepmother Eri, he notices a hickey similar to the one he had given to Eririn!