This is an easy one. Simply peel a banana (you can eat it later), slip the peel over your penis, and masturbate with it. The banana slime is a great lubricant. You can warm up the peel in the microwave for added sensations. Also, you might have better results if you peel the banana by making just one cut in the peel and removing the fruit through the single cut; you can then cut off the end of the banana peel and insert your penis through that end.