LOL!
You are reminding me of an episode of Seinfeld, I think; someone sends someone a gadget from The Sharper Image or one of those stores; it's called a GayDar. It's magnetic, to detect coins, but the character passes it up and down his body and it begins to beep near his personal area, because of his belt buckle.
I apologize for the lack of specifics but it has been a long time and maybe it was some other show. The shows I watch are Friends and Seinfeld, so I am guessing the latter.
Maybe some other smarter FReeper can clarify things. :) In any case, it was pretty funny!
It was the Office and Jim sent one to Dwight. Great episode.