This is probably the cause, then. Black Dynamite is hoping your nude freefall will be captured on camera and broadcast internationally, robbing your death of solemnity while it is looped continuously on news shows with amusing slide whistle noises. Also, not to put too fine a point on it, but it's very chilly at an altitude of 20,000 feet.
Your penis is going to look hilariously small on national television.
If at all possible, try to panic. Thrashing around will create air resistance. This will fight the gravitational force pulling you rapidly towards the ground.
No, that would be idiotic. But it will effectively take your mind off of the very sudden impact you're about to experience.
It is true that the velocity of your descent will cause you to lose consciousness prior to impact.
However, it's important to note that hitting the ground at a terminal velocity of 120 miles per hour tends to be a bit of an attention-getter. So you'll probably wake right back up just in time to die horrifically.