Serves: a party
1) Make an herb infused simple syrup by combining the mint, basil, sugar and water in a pot. Cook over medium heat until the syrup turns clear.
2) Strain the syrup into a pitcher. Squeeze in the lime juice. Stir in the rum and coconut milk. Add wedges of lime and sprigs of mint to the pitcher for color. Pour into a highball glass over ice. Top with seltzer.