I use a top sheet and I've never had any serious problems with it running away from the blankets on top. Additionally, I don't tuck it in. I find using a top

I use a top sheet and I've never had any serious problems with it running away from the blankets on top. Additionally, I don't tuck it in. I find using a top sheet _vastly_ superior to not using one, as it's far easier to wash sheets than it is to wash bulkier blankets -- they fit in the washer and dryer better. Whatever is touching you directly should be washed frequently and it's much easier if that's just a sheet.