"Pea"down the phone

We used to sell r18 dvd`s from our uk site before trading standerds stopped this due to video recordings act and hard core dvd`s being sent in the post,so we used to get calls from customers asking about the film content and the pictures on the covers.i never really gave it a thought people rang and i told them big this,wet that,large thing,small that,just a quick run down as to what was on the dvd.then after a few weeks i noticed that a certain guy would ring a couple of times a week and i would know his voice,lets call him MR X...
every time he rang the same thing over and over again then one day in the mit`s of this call it dawned on me that he was getting off on the descriptons and cover pictures that I was describing to him to the extent that I could here him pulling his pud down the line..so the next time he rang I had a very loud pea whistle ready for him and guess what he never rang again