Piggy Pag or Bee Porn?

I've never seen this before. I first saw these two bees on the drive way. By the time I'd sorted my camera I'd watched them both fly in this position to a bush. They landed and wriggled under a leaf. I scampered over and by which time I could see them with the one underneath clambering with his "passenger" on top of the leaf. Had one shot - then they took off, still attached and blew away in the wind. Only had the one shot, not the sharpest, but novel. I wished I'd managed to capture them in flight, but too windy and too fast for me.