Authentic Edo period original, c.1838, Japanese shunga erotic art woodblock by Keisai EISEN (1790-1848).  From the shunga series, Shunshoku hana no shizuku (Erotic Drops of Flower Petals).  Shunga picture measures 27 cm x 23.5 cm.  Very good colors and impressions. Condition is good with some wear and soiling. No backing. Please see and judge from photos.
 
A great Japanese shunga scene of a woman being taken from behind while enhancing her personal enjoyment by fingering herself!