Maybe you could find a way to use a belt or something to tie up around more or less your waist, pinning your hands to stay glued to your sides. This would be confortable to sleep without much problem, you could even turn around to find some more confortable possitions

! If you wanna make sure that you will not use your hands, your could maybe use a gove or something as a mits to avoid you to use your fingers

! That way you would be helpless during the night XD! Just make sure that you have a way to escape and remove the gloves during the morning XD!
Ah! And before you do all that that I said, make sure that you alread have your legs well bound and well gagged too XD! To avoid your mouth to be dry, use duct tape around your mouth and don't put anything inside. You will be well gagged and will not have any type of cloth inside of your mouth to make it dry XD! Sleeping masks are a good option for use as a blindfold while sleeping, but you could use any type of clothes, including bandanas, just make sure that they are not so tight that it can irritate your eyes or be unconfortable to sleep XD! That way you will have a really fun and confortable bondage night XD!