[Closed] Advice needed: sending a turd in the post.

OK there's someone special in my life who deserves this.

But...the practicalities.

How to package? I am thinking a small clear plastic box. I feel a Ferrero Rocher would be a bit over the top. (though I could easily fill one). Where could I get something smaller - ideally that would go though a post-box slot, so I can under-stamp it.

How do I stop the turd rolling around in the box and becoming a squishy mess? Is there some sort of transparent plastic spray that sets to solidify it? Or will I have to make a cast and just send a copy (clearly second-best, no matter how well made - and heavier/more expensive to post, unless I use expanding foam).

Perhaps I could encase it in solid perspex? Might this get round the "list of prohibited items"?

Your tips and experience welcome please.