Am I on my own with this question? In my 33 years experience of cats, I can safely say I have never come across this.

I have a chunky (fat) fluffy british shorthair who needs a good grooming every now and then.

When I groom him (especially the beck of the legs where it gets all tufty) he does a little poo. Why is this? Have you experienced this?

He doesnt get stressed when I groom him, infact he lies down and loves it, but its not nice to brush the hair and have a small trail of poo on the brush the same time.

Could it be that I'm stimulating him?

Please advise.

it is what mother cats do to encourage their babies to be a good boy or a good girl.