Foam Roll (if you have a long one, sit on the edge of it and then lay back so your spine is along the length of the roller).
Stretch + Sleep on Floor. Rotate from back (hit your stretches here. Knees to chest. Roll up, hands to toes. Butterfly. Child's pose etc.). To Side. To stomach. To other side.
Deep breathing through all of it. Tighten your ads a bit when you breathe so you almost breathe through your back. It'll make sense when you do it if you don't know what I mean.
If you do those stretches before bed when you're sleepy, it should knock you out and make sleeping on the floor easier.
