I am trying to find story (usally I can remember what they are called)

Have looked through ALL the titles, and even done Google search.

Synopsis :

Guy arrives home late - sees ad for Castration device on TV - demonstrated with 'voulenteers' from audience - orders it and gets free penectomizer as well - leaves it lying around - his flatmates use it.

Help!!!

I wrote that one. It's under my name on the author index as "The H.S.C.D.".

Thanks - Just couldn't remember the name!