What Causes Sticky Bowel Movements?

I have some form of bowel disorder or dysfunction. My stools are generally quite soft, and almost sticky/gluey - is the only way I can describe it. The sphincter doesn t seem to work properly at times, sticky stool portions remain attached - this takes a great deal of cleaning at each bowel movement to properly remove - at times there is slight leakage occurring to stain underwear. Some days I need to use paper towelling most of the day as a blotting tool in my underwear to avoid soiling. I have no pain whatsoever, nor even any discomfort, but very occasionally quite a bit of gas. I have never seen blood in the stool, and several stool samples given in recent years have shown nothing of significance re: a problem. I am 76 years old, and have a varied, acceptable diet - at least to my knowledge.