The fur around Dylan's bottom was really long so we used to cut it with scissors but he sat at the litter tray in a rather strange position sometimes
and so sometimes 'bits' would stick to his tail also. I mentioned this while he was being groomed and so she clipped the area really short. She also did the top bit of under his tail, (if that makes sense!) so 'bit's' wouldn't get sandwiched! We then bought a pair of Wahl clippers from Argos and trimmed his trousers, bottom and under-tail. He didn't mind the sound too much and I think he preferred that to us chasing him around the house with a box of wipes
And I preferred that to finding "Dylan patches" as we called them... on the bed, sofas, bath mat, carpets and best of all my bath towel that he had conveniently knocked onto the floor and slept on
Hope Gizmo sore botty is feeling better today