Can't Touch This

Saw this around the neighborhood. It's probably old news -- in fact, there were identical stickers on other nearby Stop signs, but I never noticed it until I drove by this one. While I frown upon the defacing of public property, at least whoever did this had a sense of humor.

Oh, and if you don't get the joke (either from the picture or the title of the post)? Well that's just my age showing.