after much debate I thought I would come here to get the correct answer. The saying “Good night, sleep tight”… what does “sleep tight” mean and where did it originate?
Others will no doubt be along with better references, but Partridge’s Dictionary of Historical Slang (Penguin, 1972) merely lists “sleep tight, mind the fleas don’t bite” as “A children’s bed-time [catchphrase]: late C.19-20.” There’s the presumably related entry on “tight, sit” in the sense of “To sit close, stay under cover, not to budge”, dating from the mid-1890s.
In our family it’s always been “… watch the bugs don’t bite”.
For sure it didn’t have anything to do with Shakespearean times and rope beds, etc. The glurge, doncha know.
From here:
When visiting Shakespears house and staring at the bed, I was told (by the guide) that it was because of the rope beds, as has already been mentioned. There was also this contraption that you used to twist and tighten the rope that the mattress was placed upon. It was thought that if the rope was tight, you would get a good nights sleep.