Is it permissible for the husband to suck on his wife’s breasts and drink her milk?

In the Name of Allah, the Beneficent, the Merciful,

All praise is due to Allah, and may peace and blessing be upon the Messenger of Allah, upon his household, his companions and those who have followed him. To proceed:

The general ruling is that it is permissible for both spouses to enjoy each other. There are no exceptions to this rule other than the two prohibitions for which there is unequivocal textual evidence, namely: the anus and the menses. It is prohibited to approach the woman in her anal passage. That is based on the authentic evidence related on the matter, such as the Saying of the Most High (interpretation): {Your wives are a tilth for you, so go to your tilth whenever or however you will…}[Al-Baqarah 2:223] And the “tilth” is none other than the birth canal [the vagina]. This ruling is also based on the hadith of the Prophet (may Allah bless him and grant him peace): “Approach from the front or from the rear, and avoid the anus and the menses.” It is also prohibited to have sex with a menstruating woman. This is based on the Saying of the Most High (interpretation): {…therefore, keep away from women during menses…}[Al-Baqarah 2:222] All that is meant by this is not to have sexual intercourse with them. Such is also the case during the period of postpartum bleeding following childbirth until the bleeding has stopped and she has been purified by taking a ritual bath (ghusl). Anything beyond that remains on the basic ruling of permissibility.

And Allah Almighty is the Most High, and He knows best.