I had one.  And it was not all that uncomfortable.  The urologist used local
anaesthetic and it didn't really hurt at all.  It's just a bit weird
psychologically.  I'm not sure what kind of risks would be involved.  The
only (somewhat) uncomfortable part was that I had a burning sensation for a
couple of days afterwards when urinating.  Don't worry about it.

In my case they were unable to complete a cystoscopy under local, so I was
rescheduled for one under general anesthesia using a "hard dilation". That
cystcoscopy was immediately followed by a TURP to deal with the stricture I
had developed after HDR Brachytherapy( as the cancer had spread to the
seminal vesicles, it was impossible to avoid irradiating the urethra during
the HDR).

You will be asked to sign a release. The biggest risk (although it is minor)
is infection.

I was treated to the cystocope twice. Both times without anesthesia. I was
suffering from post RP strictures (scare tissue). The procedure is
uncomfortable. (The doctor tells you to "please relax" as he inserts the
tube. I managed to slap the attending nurse.) You will feel a pinch as it
enters your penis and then minor discomfort. If the doctor is nice you can
view the proceedings on a TV screen. There is nothing like a look at the
insides of your bladder. Then out it comes, you get dressed and mutter,
"that wasn't so bad."

My biopsy was a lot worse than the cystosopy.

-- Nick