Yes, I have a butt light.
Where it came from, I don't recall, but it was probably some part of a bicycle pack from a few years back. I've had that bike for a few years, but only this year have I ridden it much, and now I'm really getting into it.
Yes, it can take Grandpa a while to get into gear.
In particular, I like to ride it around town in search of food. What it means is that I can have a drink with dinner, and not have to worry about making a memory at that one check point on that one day when the beer was especially good. More to the point, the ten-mile round trip goes a long way to negating the caloric load, and before you get all so excited about what something might cost, you might pause to consider the price of blood pressure and cholesterol medications. They ain't cheap, and side effects, in my case, make me feel my age, which is so not good.
The problem is that I've grown accustomed to the long days of summer, and now with fall approaching and daylight saving time about to expire for the season, it's easy to be out after dark. Hence, the butt light.
I suspect it was made for runners, and I've seen such lights for sale at Home Depot, though why is a very good question. However, the bigger, the more important, question is: Does it make my butt look fat?
Well, fatter is the better, more appropriate, word, and thank you for bringing that up. This is why that bike needs disk brakes.