This method of feeding should not be used if the outside temperature is much below 50 degrees Fahrenheit as the bees will not want to venture away from the warmth of the cluster to collect the feed.
Fill baggie 3/4 full of feed (honey, syrup). Lay on top bars. Do not over fill (3/4 full max.) or feed will flow out when the cuts are made in the bag. You can also set the baggie on top of a queen excluder if removal of the baggie will be required at a later time for frame inspection.
Make two or three cuts in the baggie, several inches apart, with a razor blade. Keep the cuts away from the edge of the bag otherwise there may be a constant flow of honey dripping from the edges. Make the cuts parallel to the hive entrance so that the feed will not run out over the bag due to the hive being tilted forward. Make the cuts about 4 inches long.
Place an empty super on the hive to provide room for the baggie and bees. The bees will quickly find the slots with exposed feed and line up to the trough.
After a couple of days, the bag is flat, the feed is gone and the bees are happy.