Possible Clues:

• Source of mother's milk
• Bottle top?
• Pipe fitting drops very quietly in the river
• Is there so very soft a source of milk in the old river?
• Sucker's reward?
• Was the priest in the river to get the milk from it?
• Desire of a little sucker?
• Milk-bottle top, possibly
• Chest projection
• By the sound of it, very soft in the middle of the river for milk