Yeah, bottom is well trained. But more importantly, he's really into getting gangbanged by those top dudes and taking their loads. So, skill plus enthusiasm. A winning combination.
Lovely riding scene. The boys demand "Spread that ass!", and the bottom boy takes 3 cocks in a row. He is so well trained that he endures 5 minutes bouncing up and down on those big cocks of his buddies. A real fuck marathon.