If you open a bottle of wine and you don't drink the hole of it, than you'd better cover it back.
But what if the cork doesn't fit back? Use some duct tape!
Step 1: Duct Tape Cork
Nowadays the corks are not made out of cork any more. They are made of plastic. And a plastic cork can't be put back in the bottle neck.
Step 2: Duct Tape Cork
Put a small piece of duct tape on the bottle neck.
Step 3: Duct Tape Cork
Cover the neck around with duct tape; make it in the form of a tube.
Step 4: Duct Tape Cork
With two fingers flatten the duct tape tape tube so it is sealed.