In medium bowl, place Bisquick mix. In another bowl or measuring cup, beat eggs and milk using whisk. Pour into bowl of Bisquick, and mix well. Place about one-third of the batter into another bowl, and using a toothpick, add a few tiny drops of green gel color; mix well. To remaining batter, add a few tiny drops of pink gel color; mix well. Spoon the batters into 2 separate squeeze bottles, which makes it easier to create watermelon shape.