The Elegant Duke's Teaching Methods is a Manga/Manhwa/Manhua in english language, Smut 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

You mean you want to play without knowing how to kiss?” Lillian, Duchess of Astrid, receives several pictures one day. The main character in the picture is her husband, Asher Astrid. In the photo, he was seen wearing a dog collar, kneeling, and being whipped by someone. In front of Lilian, even with a calm smile, he had never seen before. Asher, who was found out about his secret hobby, asked for a divorce from Lillian, but she rejects him and offers punishment as a reward... The secret teaching life of the elegant duke couple begins.