Colonics

After clones of, a Professor, and PAND-R were created and shrunk down and sent inside Iris, to defeat a lurgy that turned out to be a giant prawn, the clones were removed from Iris' body, which she admitted in a letter to Panda had something to do with colonics. (PROSE: From Wildthyme with Love)

Behind the scenes
Colonics, as Iris referred to the procedure as, is. The procedure involes water, or a similar liquid, being filtered through one's colon, hence Iris' displeasure.