Yomawari Sensei is a Manga/Manhwa/Manhua in english language, Seinen series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.nl fastest updating comic site. The Summary is

The author, a high-school teacher, recounts his 12 years on “night patrol“ in Yokohama City, where he comes face to face with youth dealing with issues ranging from self-mutilation to drug abuse.