Start your stretch in the low part of the banana, work towards the back and around, the front is easier, save it for last.
Use a natural material or something that has some level of stretch, vinyl, leather, fabric.
Find a way to compress the foam as you stretch and roll over the edge. Use 3M adhesive when you wrap the edge and clamp it well, let the glue set up. walk away and let it set up or you'll be tempted to mess with it.
Plan on it taking a long time.