If your best friend is a real BFF, she'll make it permanent and get inked with you. After all, your friendship never happened unless you get a tattoo . best tattoos between friends for you to use as an inspirational guide.
World Map tattoo. not sure about the placement but how cool would it be to have a small world map somewhere and just get a dot of color everywhere you travel? I've always wanted to do a map on the wall, why not on my body!