Materials to be prepared include: 1 straw and elastic band.

First, prepare a straw.

Second, put one end of the elastic band through the straw, you can rotate it and stuff it into the straw, which is faster.

Third, after the picture below.

4. Pass the straw through the opening of the elastic belt of trousers.

5. Pass the straw through the other opening.

6. Finally, take off the straw, so that the elastic band can be easily worn out.