Sounds great, but ideally I want something that isn't uncomfortable to hold, and I suspect a large plug made of soap would be.
I was thinking chocolate, dark especially as that wouldn't melt so quick and I had an idea about the mould.
I was thinking of using a normal rubber butt plug, standing it up in a plastic pot or similar, then melt down lots of ordinary wax candles, pouring that wax in the pot all round the plug.
I figure once it's cool and hard I could take the solid piece of wax and cut it down the middle in two halfs, hopefully then removing the plug to leave a perfect image of it in the wax.
I could then tie the 2 halfs back together to recreate the whole, and then pour something like chocolate inside to create a replica once cooled of the original plug, but now made out of chocolate or whatever else is suitable
The only requirement would be whatever it was would melt at temps lower than the wax mould otherwise it wouldn't work, but I figure chocolate melts in the hand whereas candles do not so that would probably make a good start.
Any ideas other than chocolate?