In saucepan cook garlic in butter for 4 to 5 minutes.
Stir in catsup, chili sauce, brown sugar, Worcestershire sauce, mustard, celery seed, salt, hot pepper sauce, lemon slices, and 1/2 cup water.
Bring to boiling.
Stir in frozen meatballs.
Cover and cook over medium heat till heated through, about 20 minutes; stir occasionally.
Remove lemon slices.
Meanwhile, split rolls; hollow out bottoms and tops, leaving edges about 1/2 inch thick.
Slice onions and separate into rings.