I dunno 'bout sittin' on the thing... but I remember both sisters, big and little, hanging off the side or rather the "corner" of the thing, fifty-some odd years ago, while the washer bounced and vibrated and almost literally crawled around the floor. They would hang off the top, and bury the corner (two sides) of the thing in their "crease," so to speak. It didn't mean much to me at the time, but years later it really got me off to remember. I still occasionally remind my older sister of it, especially when we're doing laundry.
And, oh yeah, definitely the spin cycle.
'bot