Elephants flap their ears to cool off. I imagine it was here scent that made him excited. She may have been feeling hot as well.

In this video http://youtu.be/Y9fpkE7DG6o at 7:17 - 7:51 the female elephant is seen flapping her ears back and forth which causes the male elephant to have an erection and almost ejaculate. How does ear flapping turn elephants on before having sex?