Since we are working with Double Knit, sewing on buttons may require a little different techinique from sewing onto thin knit or material. The button hole with bulky knits can be very thick when placed onto the button.
When sewing the button onto a thick piece of knitting, you want to use the yarn whevever possible and leave some space between the knitting and the button. That way, when you button up, the knitted buttonhole will lay nice and flat and not ‘bunched’.
Lace the yarn thru the button, pull the ends of the yarn thru the knitting. Leave enough space between the button and knitting for the thickness of the buttonhole piece. Bring one strand back up to the button and wrap the yarn around the sewing yarn that secures the button, so that the button ‘stands up’ and retains the spacing. Pull the yarn tail back into the knitting and knot the 2 ends of yarn to secure.
Now, no bunching-it lays nice and smooth.
I find it difficult to get all the buttons the same gap so I use a piece of cardboard with a narrow ‘v’ cut in as a spacer to get all the buttons the same space behind the button.
A row of half hitch knots holds better (long term!) than just straight wrap around the loops holding the button on.