Place the plain drumsticks directly on the grill and let cook for 25 minutes, turning once while cooking.
Meanwhile, add the sauce ingredients in a small sauce pan and let simmer on medium low while the drumsticks are cooking. You do not want to boil, you just want to heat the mixture so the flavors meld and it thickens a tiny bit.
Remove drumsticks from grill and place in a large bowl with a lid, pour the sauce over the drumsticks, place lid on bowl tightly and shake the bowl to evenly coat the drumsticks.
Garnish drumsticks with any additional sauce left in the bowl.