First of all, yes I've had it happen to me before and it wasn't fun. But I have since learned to control my wheelies so I don't have that problem anymore.
Not trying to be hard on you, but if you are not already proficient with wheelies then trying to wheelie over a bump at 90mph is not a good way to start out. Check out the numerous wheelie101 articles and practice in a safer place.
You can do several things to avoid the nutcrushing. Don't do wheelies is the simplest answer, but it's undoubtedly not the one you're looking for. Gripping the tank harder with your knees, wearing a cup, etc., doesn't address the real problem, which is poor wheelie control. If you're not controlling when and how fast the front comes down from a wheelie, you're not controlling the wheelie--you're just launching it up and hoping it doesn't go too high or hurt too much when it comes down.
Roll on the throttle as you bring the front wheel down and you should be able to set it down without slamming your jewels on the tank and busting fork seals.