It will be a challenge to machine quilt on my Pfaff!
Last but not least...
Take 2 squares of Polar Fleece fabric, cut approximately 4" larger than the cushion.
Lay the fleece wrong sides facing each other and the cushion sandwiched between.
Rotary cut slits along all the edges up to the cushion (aprox 1" apart)
Tie all the strips together to close the edge. Done!