An apparatus having a tube section and an expanded end. The tube section is flexible while the end section is rigid. The apparatus has a central bore, large enough to loosely receive an endoscope tube, and the end section has two peripheral bores which communicate with the central bore. There is a collar around the central bore which allows formation of air- and water-tight seal with the head of an endoscope. The tube may be fenestrated at its proximal end and may include medial pleats. This apparatus is mainly used by: sliding an endoscope into the central bore until the endoscope head forms an air- and water-tight seal with the central bore; connecting a lavage tube to one peripheral bore and a vacuum tube to the other peripheral bore; inserting the endoscope and the apparatus into a GI tract; and manually controlling the apparatus to apply lavage and vacuum.