Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) narrates from Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) that he said: One day I kissed (my wife) while I was fasting. Then I came to the Prophet (peace and blessings be upon him) and said: Today I have done a grave thing: I kissed while fasting. So the Messenger of Allah (peace and blessings be upon him) said: "What do you think if you rinsed your mouth with water while fasting?" I said: There is no harm in that. So the Messenger of Allah (peace and blessings be upon him) said: "Then in what (is the harm)?"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8255
Asim bin Laqit bin Sabirah narrates from his father (may Allah be pleased with him) that he said: The Messenger of Allah (peace and blessings be upon him) said to me: "Pass water between your fingers, perform ablution thoroughly, and when you sniff water into your nose, do so deeply, unless you are fasting."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8256