The Cumulus. There's no finer mattress in the world. It's just like sleeping on a cloud, because that's exactly what you're doing. It just happens to be a cloud that's been saturated with pegasus magic, to the point where anypony (and anyone) can rest upon it. The support is perfect, the temperature ideal, and Rainbow would do a lot to own one -- except saving up for it, because that's clearly stupid.
But the company has a factory in Canterlot. One which just started offering tours to the public. So in theory, all she has to do is get in there, see how it's done, and then apply that to creating one herself. Getting locked in after hours wasn't part of that plan, but if you're going to be stuck anywhere at night...
A mare who loves sleep, and sixty of the world's best mattresses.
Welcome to one of the worst nights of Rainbow's life.
Cover art provided by Rambling Writer, with thanks.
(Now with author Patreon and Ko-Fi pages. The current Ko-Fi drive is for a new mattress. That is why this story exists.)
(The author is not subtle.)