I think tentacles are a pretty natural fantasy. The are shaped just right but they can do things inside you that a regular guy can't. Personally I am pretty much a typical Asian gal and find them pretty arousing.
The origins can be traced back to old shugna art. I think people back then had to be more creative about sex toys. I have heard old tales that women would use a live octopus for pleasure in some of the fishing villages.
Anyway, I'd try the tentacle toys for fun.