Girls: Freeze a banana (remove the peel) and masturbate with it as you would with your finger, until you orgasm.
Guys: Take a banana peel and make a slit in it and remove the banana itself while trying to keep the peel in tact. Then microwave the peel until warm (about 15-25 seconds on high). If it is too hot, wait a little for it to cool. Once at the right temperature, put your dick in the banana and jerk off.