The achievement can be found at the beginning of the track Ever, Everer, Everest. Reverse at the start line and you will find a basketball floating in the air, reverse a little behind it and bail towards it while holding Y. Keep holding Y and you will be lifted to the top of the mountain, this will take many attempts to get right so don't worry if you don't get it first time. When above the hoop stop your rider with the right stick hold down and left to position him over the hoop, or let go of the ball and immediately grab onto it again, then make sure the ball goes into the hoop. The achievement will then unlock.