Pete is right. You want the seat to have a climbing angle so your thighs are supported not just to bottom of your butt. Sitting on a flat seat puts all the pressure on the lower butt and cuts off the nerves and blood vessels at that point - a lot like sitting on a hard wood floor in the kayaking position. By raising the seat to an uphill angle, you are dispersing the pressure. You want as much of you supported as you sit in the kayaking position with your knees elevated. That will relieve your problem. Even a hard fiberglass molded seat in an uphill angle will give you more relief than a flat padded one. Also make sure your foot pegs arn't too tight. Rou want a forward bend to your feet - nor too straight up.