Step 1: heat the port tongs to a very high temperature quickly — I use a campfire burner for our purposes.
Step 2: once the port tongs are red hot clamp them around the neck of the bottle right below the cork, but above the wine. Hold for 5-10 seconds, rotate 90 degrees and hold for 5 seconds
Step 3: grab a squirt gun (we keep ours in the refrigerator) or a cloth dipped in cold water, remove the port tongs and place them in an ice bath, immediately squirting the hot glass with cold water, the neck should break immediately.
Step 4: carefully remove the top of the bottle and pour into a decanter through a filter (you want to make sure to remove all chance of small broken glass)
Step 5: drink as you would any other bottle!