Thank you for helping us by reporting bad content.
What a sweet idea! I love bananas and defiantly want to try this. The website(in the source link below) says to use a toothpick or a mechanical pencil with no lead to write the message. Don`t apply too much pressure because all you need is a slight indention. I wouldn`t push too deep because then person receiving the message might see it before it`s ready. I recommend not using this for purposing unless she really likes bananas. Image not mine!