Have you ever wondered where the expression "Sleep Tight" came from?
Well I know!
I learned it one day on a trip to Conner Prairie Farm!
http://www.connerprairie.org/It's an old pioneer expression.
Back in the old days, way before box springs and space age memory mattresses, the beds had ropes, crossed threaded under the mattresses to hold them up. But ropes being what they are would soon stretch out of shape and therefore several times a week it was necessary to tighten them back up in order to keep the bed mattress from sagging down to the ground.
So, if you "slept tight" this would indicate you had slept on a mattress supported by freshly tightened ropes, firm and flat rather than a saggy mattress dipping down to the floor.
And Yes, there really is such a thing as bedbugs.
They bite and itch (very much like chiggers) and they can often be found in mattresses and unlaundered bed clothes. So now you know what the expression "sleep tight and don't let the bedbugs bite" means.
We learn something new every day, don't we?