Use your toilet roll to draw the circumference out on to felt. Cut this circle out.
Cut a rectangle of felt that is long enough to fit around the circumference of the roll and wider than the height of the roll.
Sew the rectangle around the circumference of the circle.
Sew down the open edge of the rectangle.
Fold inside out and you've made your cosy.
If you want to decorate the cosy with sequins, here's how. Bring your thread up to the front of the cosy and through a sequin, sew through a bead and then back down through the sequin. Continue this along until you stitch off at the end.