Place the marinated pork and its marinade on top of the banana leaves and sprinkle with
oregano. Halve the orange and squeeze the juice over the top, then throw the entire orange in there. Fold the banana leaves on top of the pork to cover and place one more banana leaf on top to ensure the pork is sealed. Cover the
baking sheet with
aluminum foil to ensure the banana leaves do not burn. Bake until the pork is pulling apart, about 4 hours. Uncover for the last 15 to 20 minutes for a crispy top. Shred the pork, then keep warm.