Systems, methods and devices for performing water-aided endoscopy (WAE) are provided herein, including an endoscopic plug with a bulbous distal portion and a separate compressible exterior housing which are designed to create a sealed environment within the body cavity. The endoscopic plug may additionally include valves, balloons and pumps which provide means for introducing and removing liquid into the body cavity and maintaining the sealed environment to prevent fluid from within the body cavity from leaking to an external environment. The endoscopic plug provides a channel for insertion of specialized tools designed to interface with the multi-functional plug for insertion into the body cavity while maintaining the seal.