If you have belly fat like I do, and sometimes have interbation difficulty, this method helps: position your left fingers about two inches over the stoma, push down a tad and pull up to make the stoma and stomach as taut as possible and insert cath with right hand (or vice versa) which will glide the cath into valve better.

Thanks for the tip! Now if I could only drop 5 kg (10lbs!) and rid myself of the fat
Sharon