I never get numb on the crotch but have occasionally on the fingers. But...by moving the seat down a bit to more even with the bars, you are not leaning into the bars, thus not numbing your fingers. I would think the same holds true with seat. If you seat is pointing down, then your butt is sliding always downwards...thus putting pressure on your crotch,...numbing the little goodies down there.

Might just try adjusting the seat....