very simple but depends on what size your item is , try a empty drink bottle either 1.25 litre or 600mil bottle if it cant fit thru  the hole just cut top off , after you put the wrapped item in bottle then tape up the bottle ,and the bottle will not bend ,you can add some paper in the bottle.

try and squeeze an empty bottle closed , 

a cardboard box will squash but try doing it with a plastic bottle.