haha, i had exactly the same thing years ago, a friend's daughter's cracking little whp. i have very long legs, i stepped over him and was on tiptoes both sides so he didn't feel any weight, but he still got very feisty about it and accelerated out from underneath me! learnt my lesson...!
my first actual (my own bought n paid for pony many years ago) was a sec a bay called jacko i rode him for miles and he was fab! i sold him to a riding school who worked him into the ground which i wasnt too pleased about a few yrs later i thought id sold him to someone who could show him for what he was ill try to scan some piccies in me and my sisters used to ride him thru the subways to get to my house then my dad would kick off cos he'd wrecked the garden
I occasionally have a wee go on my sons shetland. Mostly when i'm bringing him in i'll have a trot or canter up the field bare back, great fun and he seems to enjoy it aswell!