Step 1: A bit of yarn
B - Chose your hardware. I used a 4mm or G hook and got a 4" banana. You can enlarge your project by using a J hook and two strands of yarn and get a 6" banana.
C - Get fluffy. A handfull of Poly-Fil Fiber will make your banana nice and squishable, without the mess of a real banana. A 12oz bag will run you roughly $3.00 and will make you bunches of bananas.