I used to always do that, LOL. I had an old Curly Top diffusing dryer (flat, round head instead of a pistol type dryer) that had this knob on that back of it so that I could first put my bowl diffuser face down on the floor then sit the Curly Top on top of it with that knob down in the neck of the bowl diffuser. Then I'd turn it on and get on the bed, first hanging face down to get the front curling good then flip over and do the back.
I used to have great hair days that way even without the products we have now - I'm talking like 1985-95 until that dryer died. Haven't found a way to duplicate those results. Different cut back then, too, though - basically blunt cut with layers only in the last few inches. Gave me lovely spiral curls in my BSL hair using Paul Mitchell Liquid Sculpting Lotion on very wet hair (I'd figured out that much even then!).
My radiant heat pistol dryer came with a holder, but I can't put a diffuser on it or I'd try it with it. Wonder if there are other pistol dryers that come those holders? Hmm, you know I've never thought to see if one of my other dryers would fit in the holder. Will have to check that out!