This is by Lynn-Paula Russell.  Lynn was once a porn-actress specializing in S&M movies, I believe.  Most of her work is about bondage, corporal punishment, whipping, caning and spanking.  That's great, but I prefer her more general work, such as this example.  To me, the best erotic art sets up a situation and leaves the viewer to make up a story to fit it.  Is this a whore with a client or a couple who have just met and, overwhelmed with desire, have resorted to a back-alley in which to satisfy their lust?  Who knows?