Well,
I've been skydiving/parachute many times, and yes padded!
Anyhow, give it a try, it's very freeing...and not nearly as scary as you'd think...I first went after a friend of mine and me were talking about bailing out of airplanes...I used to fly aerobatics for many years...anyhow, neither had ever done parachuteing in a n way, and neither knew if when needed would really bail out...or instinct to keep flying...
So, we tried it...and it was an experiance...one everyone should try once...
As for feelings/being able to use a diaper...shouldn't be an issue...and there isn't much pressure of any real kind on you but wind pressure...