This is more simple than the other answer. Go to the town or the plaza, and you'll find two penguins.talk to them . they'll show you their puffels tricks and one of them will get them stuck in bubble gum... secondly agree to help them and click the bubble gum, if it doesn't work wonder around the island then go back.... finally ask them if you could take some and stick it in the duck hole....
then you might find a pump of the dock guy help him first pull the string on his boat... then put the pump on the duck in your inventory and pump it...
