Question: What is the ruling regarding that which some people refer to as “oral sex”?
Response: Allaah has not permitted (sexual) intercourse (oral sex) for the man with his wife using the mouth, never!
And none pursues this path other than the one who does not have any upright moral character, even if he is (happens to be) from amongst the Muslims; And that which is apparent is they (the Muslims) have taken this (habit) from the disbelievers through (watching) pornographic films.
So that which is obligatory upon the Muslim woman is not to allow her husband to do this.
Shaykh 'Ubayd al-Jaabiree