All you need is just a simple plastic bag. The size doesn't matter.
Put it horizontal and fold into half.
And once again fold into half.
Then start left or right (I usually start from left) to fold a triangle.
Keep on folding the triangles untill...
...you almost reach the right side.
Then fold the right side to the middle...
Then fold a triangle with the right side (do you still get it ;-)? No worries, I have made a short video which will be much more easier to follow ;)!)
Like this ;)!
Find a hole on the lefter side...
...and put the righter side into the hole.
Tadaa! It should look like this :-)!
Here is a short video :)!
Fancy, decently and easy to carry in your handbag and easy to find it when you need it :).
You can use any plastic bag :-)!