Midrash Lekach Tov

When the manna would fall upon the camp at night, the dew would first descend and spread out as if it were a fine cloth, so that the manna would not become soiled. Then the manna would descend upon it, and afterward another layer of dew would come upon it from above, as it says, ‘When the dew fell upon the camp at night, the manna fell upon it’ (Numbers 11:9). The dew came to protect the manna from the snakes and scorpions. The dew resembled a woman's breast: just as an infant finds nourishment there, so too the manna came down between layers of dew, and each person would open the door of his tent and find his sustenance prepared,⁠a ready for eating and drinking, fresh as though drawn from the sun and the moon.