Melt butter in a large skillet or chafing dish; add sugar, and cook over medium heat until bubbly.
Peel and juice orange and lime halves; reserve peel and juice. Add peel to skillet. Stir in Triple Sec; ignite with a long match. When flames die down, add juice of orange and lime. Cook over medium heat until thickened and lightly browned. Remove fruit peels; discard. Add mango; bring to a boil.
Place tequila in a small, long handled pan; heat just until warm. Ignite with a long match, and pour over mango mixture. Baste mango with sauce until flames die down. Serve immediately over coconut ice cream.