Apparatus and methods for extending a tube, the apparatus including a foldable tube having a folded portion inside an unfolded portion of the tube, and a source of fluid coupled to the unfolded portion for providing fluid into the unfolded portion to unfold and extend the folded portion out of the unfolded portion to become an extension of the unfolded portion. The apparatus and methods are useful, inter alia, for cleansing the colon in the normal direction, that is, from the cecum to the anus, using an apparatus that is introduced via the anus. A washing liquid is supplied deep into the colon via the soft feed tube that is inserted via the anus and is extended into the colon by inflation. The washing liquid is then drained out via the anus through a drainage channel.