If its bizarre (considered by the majority at least), would you even tell your mate? how would you say it and when?
Yes, you should tell her. Whether she initially wants to do it or not, she will appreciate you sharing your thoughts and fantasies with her. More often then not, once she thinks about it a little and gets used to the idea, she will likely be willing to try it. I like roleplaying and women love new ideas for sex-play. I also like using anal beads and ben-wa balls on women, and they usually warm up to the idea after pondering it for awhile.
If she likes you, she'll be likely to try any idea you have sooner or later. Don't press her; but just put it out there and then focus on regular lovemaking while she thinks about it.