Chapter 90.5 of Kamisama Hajimemashita.
When Kurama Shinjirou had just left Kurama Mountain, he was taken aback by the unfamiliar changes around him. In the present, Mizuki comes to visit him to learn how to live better in the human world. Mizuki takes note of how long he spends time in the shower and how many times he poses in front of a mirror. Kurama is annoyed and refuses to teach him, telling him to go to Tomoe instead. However, Mizuki tells him that it was Nanami Momozono who said the Kurama was such an expert. Flattered, Kurama tells Mizuki the rules to fit in well. His first rule was to find a place to stay by mixing into the human society, such as he did by joining an orginazation. The second rule was to find money. Kurama recalls having to ask for a job but was rejected for being too young. The third rule was to not go with strangers into a dark place. Kurama remembers doing so and it led him to having his identity found out. Rule four was to learn that the human world changes frequently, as he found out when the orginazation he relied on disbanded. He tells Mizuki that one must learn to change oneself but rule number five was that you must never forget the person you want to be. Mizuki tells him he was touched and while Kirama answered his phone, Mizuki finds a old photo album finding odd pictures of proof of what Kurama had to go through to fit in the human world so well. Mizuki is stunned at the difficulty and decides that perhaps he should ask Tomoe instead.