
Chinese shunga. This sounds like nonse because shunga is a distinctly Japanese art form, with a Japanese name. But at the same time the Chinese have erotic prints which are very similar to the Japanese ones, the only difference being in style. The sample here is a very special one because the couple is doing it mounted on a horse back. The man is possible a barbarian of some sort.
Also, pay attention to the lady's socks which are interesting not so much because it is funny to see someone stark naked wearing socks but because she obviously has those notorious bound feet of the Manchu aristocracy.