I have an ileostomy and was told by the surgeon never to allow anyone to irrigate or give me any sort of an enema through my stoma. He also said never to take any sort of laxative as it could blow my intestines apart.
As for obstructions, I get them 2-3 times a year and have been in and out of the ER too many times. For the most part, I know that after I eat the giant bag of popcorn at the movies with the extra butter, I KNOW I'm gonna pay for it. For the most part, I avoid anything with a skin or peel it, then chew it really well. Nuts? Forget it...I don't even go there anymore. I stick to eating relatively soft foods to make sure things can flow easily to avoid the dreaded NG tube. However, there have been 2 occasions I have actually gone into the ER and said, "GIVE IT TO ME NOW!!!" Even reinserted it once MYSELF because when I told the nurse it was going to fall out, she didn't believe me. A good cue for me is when I start throwing up the blacky/greenish bile.