Roller Coasters & Sore Bottoms

There's an Endart drawing of a coin-operated fairground ride - a wooden horse with a wheel of spanking paddles behind it - that I 'borrowed' for 'Uncle Albert's Spankoscope'!

I had one of my characters go horse riding immediately after a caning, but it was a detail in a much broader story.

This inspired me to add an element of roller coaster soreness to a story I was working on. This was just published as "Betting Her Ass".

I have tried several times to find the story of the London bus with the bad seat. The girl has a sore bottom and bounces up and down on her trip. I believe it's about Kane Strokes. Any help would be very much appreciated by me.