What is the ruling on a husband fondling his wife's tongue, and what is the evidence for that?

It is permissible for a husband to caress his wife and enjoy her body, with the exception of anal intercourse or vaginal intercourse during menstruation, or while in a state of ihram or fasting. The permissibility of foreplay involving the tongue is indicated by what Al-Bukhari narrated from Jabir regarding the Prophet's (peace be upon him) saying: "What is the matter with you and virgins and their saliva?" This contains a reference to sucking the tongue and sipping the lips. It is also indicated by what Ibn Khuzaymah, Imam Ahmad, Abu Dawud, and Al-Bayhaqi narrated from Aisha, that the Prophet (peace be upon him) would kiss her while he was fasting and suck her tongue. Ibn Al-Qayyim mentioned that among what should precede intercourse is foreplay with the woman, kissing her, and sucking her tongue.