At last the Incontinence Lady visits to check on my mother's condition and find out whether she needs the mountain of incontinence pads that is piling up in our basement. Because my mother is not incontinent at all. She's just scared stiff that one day she will be and we will be unprepared, so she must stockpile these things and often wear them day and night, just in case her bladder and bowels suddenly lose their grip on things.

Usually they have too tight a grip, so the talk turns to constipation. What a treat for my mother. Now that she is very old, her bottom often preys on her mind. When one is lying in bed, bored sick by the telly and too exhausted to read, it is difficult not to consider one's body, especially if part of it is clogged with toxic cement.

But who can my mother share her bottom thoughts with? Only me. Most people tend to mock or shy away from this topic. And there are times - meal times, or times when I am feeling artistic or sensitive - when even I recoil from bowel talk. Now, at last, here is someone happy to chat about blockages in a robust and upbeat way.

The Incontinence Lady understands. She knows why this ailment can fill your every waking thought, and better still, she knows that things can be even worse than we suspected. She has constipation stories to make the jaw drop. She even silences my mother - a rare power. We both sit, gaping and speechless.

This is an ailment, says our visitor, that can kill if you refuse to deal with it. "It can back up to here!" says she, pointing at her chest, "and then... "

The rest is too frightful to relate, but my mother and I scream with a ghastly sort of excitement. Rosemary's sister, a nurse in the 50s and 60s, confirms these tales of horror. Lie in bed all day without drinking quite enough, and you're done for.

So my mother must drink gallons of water daily, which means running to the lavatory all night. She is infuriated. There is no peace for the constipated. For those in the opposite camp there is at least some consolation, says Fielding. "Elvis the King wore nappies at Vegas!" But my mother doesn't give a shit. She couldn't anyway.