Hadith 5:49
‘A'isha said that the Prophet used to kiss her and suck her tongue when he was fasting. Abu Dawud transmitted it.* * Saum , 34. This is said by some to be weak because Muhammad b. Dinar and Sa'd b. Aus are among its transmitters.
عَن عَائِشَة: أَن الني صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: كَانَ يُقَبِّلُهَا وَهُوَ صَائِم ويمص لسنانها. رَوَاهُ أَبُو دَاوُد
Original Reference: Mishkat al-Masabih 2005