"In Victory We Deserve Champagne...
In Defeat We Need It."
Le Sabrage (a.k.a. sabering a bottle of champagne) became popular after the French Revolution when the saber was the weapon of choice of Napoleon's fearsome light cavalry (the Hussars).
One of the tales about this tradition is that Madame Clicquot hosted victory parties in her vineyard, and as the dashing officers rode off in the early morning they would gallantly saber a bottle of Champagne to impress the rich young widow. (Now, of course, they would drink from my Reserve - in the company of an exquisite beauty.)
So Let's Bring Out Your inner Hussar...
Step #1: Choose Your Weapon
Be bold. If you've purchased a pricey Champagne saber, whip it out. Otherwise, a solid butcher's knife will do just fine. Have some glasses (and maybe a couple of towels) handy.
Step #2: Have Very Cold Champagne Mon Ami
Be sure to start with a bottle of Champagne that is very cold (38-40°F, tops). Remove the foil wrapper and little wire cage. This will make for a clean break, although some people say it's not necessary to remove the packaging.
Step #3: Grab It (by the derriere as we French say)
Grasp the bottle properly. That would be firmly, by the base, and pointed away from any onlookers. Hold it at a 30-degree to 45-degree angle. Find one of the two vertical seams running up the side of the bottle to the lip. That intersection with the lip is where the bottle will break most cleanly, and that's where you want to aim your stroke.
Step #4: Don't Succumb to Performance Anxiety...Be Bold &Take Action
Hold the knife flat against the bottle, blunt edge toward the top with the sharp edge facing you. Run your saber or knife slowly back along the seam toward your body. Then, quickly and firmly thrust it back up the seam toward the bottle's tip. Strike the lip sharply, making sure the leading edge stays down and in toward the crook of the lip. Apply a solid follow-through.
Step 5: Get it in the Glass (unless you are christening a boat)
If you've performed the task properly, the cork (with a ring of glass around it) will fly off the end of the bottle. You'll then begin pouring the bubbly, and humbly say "a little trick I learned from Henri" and offer a very clever toast.
Beware mon ami ~ like the Napoleonic Wars, this is not without its hazards. May I reccomend a few successful efforts before trying on horseback?