Freshly corked bottles of wine are usually left upright for a few days to allow the corks to swell and give a firm seal around the bottle neck. After that they can be layed on their side for a good age in your cellar (the cupboard under the stairs) The very last process is to add a shrink cap to the bottle to help keep the cork from drying out, decicating and letting all your hard work leak over your floor.
I used to use a hair dryer to shrink the caps until a kind soul pointed me towards using hot water. All you need is the correct amount of water to just reach the submerged cap. Get it to a boil and then remove from the heat, plonk you bottle in, push down to the base of the pan and count to “two.”
Hey presto you have beautifully capped wine that looks all sophisulcated.