Half Watermelon and remove flesh in bite size squares. Keep the outer shell for filling later. Put the watermelon flesh in a large zip lock bag. Add the tequila. Split the chillies and remove the seeds. These are the hottest part. shop the chilies finely and also add to the bag. Mix the ingredients up in the bag and and chill for 2 hours. When the guests arrive pour the contents of the bag into the watermelon shells and wait for the approval of all your friends.