Musnad Ahmad 26:564

Waki’ narrated to us, Sulayman ibn al-Mughirah narrated to us, from Abu Musa al-Hilali, from his father, that a man was on a journey, and his wife gave birth, and her milk was retained. He began to suck it and spit it out, but it entered his throat. He went to Abu Musa and said, "She has become forbidden to you." He said: So he went to Ibn Mas’ud and asked him. He said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Nothing makes [marriage] forbidden through suckling except that which causes the flesh to grow and the bone to develop."