It's also useful on picnics on boats.
Most likely you'll use this instructable to drink other people's wine for free.
"If i open your bottle with this piece of string, can I have a cup?"
Step 2: Push the cork into the bottle
using a pen or a bolt works fine (just push it in slowly to prevent wine spilling out)
I've seen the hardest core of people do this with ninja finger tricks. If you support your pinky with your other hand you can push it in with your pinky. This might hurt a little, but you'll feel real bad-ass...
Step 3: Tie a stopper knot in your piece of string.
The best stopper knot generally is the figure 8 knot. Look at this sequence of images to learn to tie it. You can use this knot everywhere. It is easier to untie later than an ordinary overhand stopper knot... Re-use your string.