(as) tight as a drum adjective phrase
Used to describe the tension of an object as the skin of a drumhead.
I have eaten so much that the skin on my belly is tight as a drum.
child blows a balloon that becomes so big that it is about to explode. This balloon is tight as a drum.
To be sealed securely, be closed a container tightly or fill something, especially so that air or liquid cannot get in or out.
Don't worry about leaks; this pipeline is tight as a drum.
Open the window, otherwise we will die because this room is tight as a drum.
Many sources point to the mid-19th century for the origin of this phrase.