Responding to the topic, Wael Shihab, a Shari`ah researcher at Al-Azhar University, holds that Islam does allow a husband and his wife to sexually enjoy themselves in the way they like as long as they avoid anal sex and sexual intercourse during the wife’s menses or post-natal bleeding.
So, oral sex practiced between husband and wife is not prohibited if the husband and his wife likes it and there is no harm in practicing it.