That's the problem that I have with a flat sheet. It gets all bunched up at the bottom from me moving around too much.
But, for some reason not so much with a second blanket.
Though, if I get even slightly too warm while I'm asleep I do push the top blanket off to the side a bit.
All the plugs are on walls with furniture against them.
I don't really feel comfortable having something like that under my desk.
And the only other place would be right beside my chair under the window, but there is the issue of potentially not being able to plug it in, as the cord would have to go around my desk to prevent tripping [I would trip over the cord all the time].