(With the enormous supply of Garcia/Morgan fics out there, it's possible this idea's been done).
Write a M/G fic based on the following quotes: Morgan: "My code of survival says 'never mess with a woman who carries a gun." ('Broken Mirror')
Morgan: "Take this gun--"
Garcia: "I don't believe in guns!"
Morgan: "Trust me - they are very real. Take it!" ('Penelope')
Feel free to mess with it as needed. Happy writing!