Perhaps it seems from the title that this post belongs in the equipment section, and perhaps it does, if a moderator wants to move it I have no objection. But I put it here because I thought that the golden age section might be frequented by more people able to answer my query.So, my question is, for how long have we had these double balloon nozzles? How much have they changed over the years? I have seen references to them from stories set in the 50s, but don't know how much direct knowledge the authors had or what kind of research they did.Myself I'm what you might call enema curious, I have never had one but they intrigue me especially as I have a definite rubber fetish. Anyway I've become intensely curious about these things, also I'm writing a story and want it to be as accurate as possible. Any help appreciated, and I hope this might turn into a good discussion/memory share.