What an interesting picture. I love images that tell a story--or perhaps more accurately, ask the viewer to tell a story.
What is happening here? The guy is lying on his back, the warm sunlight coming in the window. What had he been doing before? Just waking up with a rock-hard erection and starting to touch himself? Did she come in an catch him in the act? She's dressed. From the lines of her underwear, you can tell she's been dressed for a while. Did she come over from her place? From work? From running errands? Clearly she didn't have time, or didn't see the need to undress before she climbed on him, reverse cowgirl. She just unbuckled her jeans, yanked them down past her butt, and hopped on for a ride.
Pretty sexy, I'd say.