Abstract: A device for forming a leakproof closure on the terminus of a tubing having an elastic wall. The device consists of a plug insertion tool and a plug. The plug is a elongate member having a convex distal end and a proximal end. The plug insertion tool has a handle portion which is dimensioned to be grasped by a user for manipulation. The distal end of the insertion tool has a rod projecting axially therefrom which is adapted to releasably engage the proximal end of the plug. The plug is dimensioned to fit snugly within the elastically distended lumen of the tubing. In operation, the plug insertion tool is releasably attached to the proximal end of the plug by engagement means such as mating threads and the distal end of the plug inserted into the open end of the tubing and advanced by means of the insertion tool. The intralumenal portion of the plug forms a leakproof seal with the elastic wall of the tubing.