Found a perfect rock!

As I look around I see a perfect rock formation. The stones are all smooth and nice. Won't scratch her body. Then it's shaped like big triangles. One she can bend over so her cute little ass is on full display. Then a smaller triangle to catch her knees and legs. She will be so exposed and at my mercy there.

Or I can sit in it like a chair resting my back against the big triangle with legs over the small triangle and she sitting in my lap with my cock up her ass! Really cozy and nice at least for me.