a willing girl or guy is fucked doggy style while being steered head-first on hands/arms down a flight of carpeted stairs. using-a-female-receiver "bonus": grab boobs for steering.
I agreed to to let my boyfriend snowmobile me because I got it confused with snowballing. Instead, I'm being fucked down the stairs. / I was snowmobiling this chick last night and it gave us both rugburn. Next time, we're wearing kneepads.