In a few decades we have grown larger and, unfortunately, bigger, so manufacturers have changed the standard sizes of clothing.
A criterion has not yet been taken into account: women have an arched back!! Result, often pants have a back gap. No need to be a great seamstress, it’s an easy fixing.

Step 1:

You need: 2 flat and thick buttons – some buttonhole elastic – sewing
thread – a needle – 2 pins – a seam ripper – a thimble (for the more clumsy...)

With the 2 pins, mark the inside of the belt, slightly wider than the elastic band.

Step 2:

With the seam ripper, cut a perpendicular slot, from one pin to another.
A pencil line would delimit as well, but the advantage of the pins is that they stop the seam ripper. No risk of going too far.

Step 3:

Hand sew a buttonhole, taking only the first layer of the fabric (you
will find on the net tutos much better explained than I could have done…). Sew the button.

Do the same steps on the other side of the belt.

Step 4:

Using a safety pin, pass the elastic between the two layers of the belt.
Attach both ends of the elastic to the buttons.

Step 5:

Et voilà, a well back fitting pants!!
The more forward you make the buttonhole, the more you will have a bloomer effect.

This technique is also ideal for large and lean children or for those who have a little tummy can. For many years, all of my children’s pants have been retouched.