Is it permissible for a wife to lick her husband's semen, and does it invalidate her ablution?

Scholars differ on the ruling concerning semen, holding three opinions:

1. Impure (najis): It must be washed whether wet or dry (the view of the Malikis). 2. Impure (najis): However, rubbing off its dry form suffices (the view of the Hanafis). They cite as evidence the hadith of the Prophet, peace and blessings be upon him, washing semen, and the hadith of Aisha, may Allah be pleased with her, rubbing it off when dry and washing it when wet. 3. Pure but considered repulsive (tahir mustaqdhar): (The view of the Shafi'is and Hanbalis). They cite as evidence the hadith of Aisha: "I used to rub semen off the garment of the Messenger of Allah, peace and blessings be upon him, and he would pray in it."

The preponderant opinion is that semen is pure but considered repulsive, based on Aisha's hadith: "The Messenger of Allah, peace and blessings be upon him, used to scrape semen off his garment with 'Idhkhir (a type of grass), then pray in it, and rub it off his garment when dry, then pray in it."

As for licking semen, it is not permissible because it is considered foul.

If the cause of ablution (wudu') breaking is touching the male organ, then it is a nullifier. However, if the semen has separated from the spouse, it does not affect wudu' unless something of it has exited.