A cystoscopy is a medical procedure in which doctors examine the inside of your urinary bladder. They do this to check for cysts, lumps containing parasitic larvae or other unpleasant infections.
It's not easy to look at the inside of someone's bladder. It's done using an extremely small camera attached to the end of a piece of fibre-optic cable; this device is known as a cystoscope. The entire examination is carried out without any kind of surgery, generally under local anaesthetic.
The astute reader will have realised two things at this point:
If you want to stick a camera inside someone's bladder, wired up with fibre-optic cable, there's only one way to shove it in there1.
If you're only under local anaesthetic at the time, it means you get to watch.
The author has had a cystoscopy on two separate occasions. It isn't any nicer the second time.