I just read the wiki article and it explains about using duct tape.
I use it a lot in the course of my work (taping dust suits to arms and legs etc) and it is very sticky and painful to pull off quickly, and can also cause skin irritation if used for long periods, as I found out.
Also, what happens when you get caught short and have to run to the bathroom in a hurry then find you cant get it off easily?
If you are in a public restroom and other users hear muffled screams followed by the sounds of duct tape being used, how are you going to explain to the police that you weren't really trying to kidnap someone?
"Honestly officer. I only came into the ladies toilet so I could wrap duct tape round my penis."
Suddenly kidnapping doesn't sound so bad.
I personally wouldn't advise using it unless there is no other alternative.