Deborah, irrigation for ostomates is only possible for patients with a lower bowel colostomy. They must have fairly well-formed stools, not liquid. It doesn't work for people with ileostomies.
However, for people who do not have ostomies, there is colonic irrigation... and that's a different deal. It's most usually done in a clinic that has a all the equipment to do it without a huge mess. I don't think they do it to keep you from having to go to the bathroom often. It is usually just to clean the colon because a clean colon makes for a healthier body. You should have regular bowel movements daily. Irrigation for ostomates helps to eliminate the need to wear a bag all the time, or to feel the constant gush of shit through the stoma, into the bag, which is something like I imagine hell must be. At least, it feels like hell, to me.
An ostomate who irrigates sometimes can wear just a stoma cap, instead of a bag, and that would be so freeing. I really would like to do that. One day I'll get around to making that change in my routine... as soon as I find the energy to pursue the discussion with my doctor.
Meanwhile, if you want your colon reamed out with a colonic irrigation now and then (do not do this daily. It isn't how we are meant to exist) here is a link to a YouTube video about the process.
http://www.youtube.com/watch?v=t-neEd0arEg