I knew of a few backpackers in Darwin who were burned by the sap. Its really sticky as well
I used to buy them by the box and cut into dlices and dry them. Great snacks for the boat
Cut the mango flesh from the skin, don't scrape the last bits from the skin with your teeth and you'll probably be okay. The chemical compounds causing the reaction is present in every part of a mango but mainly in the sap.