Hi katswhiskers, I am not implying that it the case with your colon therapist, but it is not unheard of for some of them to discourage home enemas because they fear if you get good results, you may not return as often for colonics.
If you are careful, and lubricate your anal sphincter and the rectal tube, and insert it no more than 3 inches without forcing it, you don't have to worry about perforating your bowel.