Use Pipe Insulation. you can get it at any hardware store. Also get some velcro (hook 'n' loop) ties to wrap around it on the ends and middle too for extra security. the pipe insulation that has adhesive strips on it already will help too for security
you can also put the foam on the rope leading directly from the handle's v like this
the ronix totem one i made (just because and for additional security) with the handle cover that came with it which makes it look more professional