My feet fell asleep in the boat because the sciatic nerve(goes from base of spine , under the butt as you sit and down the hip to the feet) was compressed and much like sitting on a water hose- there was less flow of neural impulses and then the sensation of feet falling asleep. So stand while you paddle the way some kids with super balance. You know the type- 7 years old and flying by you on the ski slope doing royal christies. I felt that whacking them with a ski pole across the knee was the only Christian thing to do. Just kidding.
So anyhow try a partially inflated paddle float under the thighs to put less weight on the butt. I use ethafoam that is about 2in by 10 and low on the outside so my legs can get down to brace. Hope this works for you.