If you're really tired, you could say "throw oneself on the bed". It's like "collapsed" on the bed. It's not that common.
"to throw oneself into an activity" means to get involved in something with a lot of energy and enthusiasm e.g. He threw himself into the role of father, regularly feeding and looking after his new baby. It's a fairly well used expression.
You could "throw yourself to or on the floor". Perhaps you are trying to avoid being seen by someone, you suddenly see them coming, and then you throw yourself to the floor to avoid detection.