Did that in my childhood on wooden stairs in my parents house. Rounded edges, kid of hazardous in general but great to slide down like this. Kind of want to try this again, but I also value the integrity of my bones.
Stair surfing - I've still done it as a middle aged guy.
I would like to learn to do it hands free, one foot in front of the other (forward and down to the next step). I can surf a bit without grabbing the rails, but only rarely make it to the bottom. Definitely needs the perfect wooden stairs to get maximum flight time!
An other variation would be to keep your feet in a 45° and then keep doing and landing on every stair edge
Never seen someone else doing that, it's insanely fast if you can master it :D