Abominable Acts during Fasting

1- Excessiveness in mouth rinsing and sniffing water through the nose during ablution.

This is due to the fear of allowing water to slip into his throat. The Prophet ﷺ said:
“... and
over draw
water (during sniffing in of water in ablution) except when you are fasting
[ Source: Abu Dawud.]
2- Lustful kissing.

Kissing is discouraged for one who is fasting if he fears the possibility of ejaculation or imminence of sexual urge. It is also necessary for him to avoid anything that invokes his sexual urge. However, if he is sure of his ability to control his urge from invalidating his fast, then he is permitted to kiss. ‘A’ishah (may Allah be pleased with her) reported:
“The Prophet ﷺ used to hug and kiss her while he was fasting.
he is the best of you, who controls his urge.[ Irbahu: Means his need of it.]”
[ Agreed upon.] This is why hugging is disliked between the youth, but not for an old man. On the authority of Abu Hurayrah who said:
“A man asked the Prophet ﷺ concerning a man hugging (his wife) when he is fasting and he allowed him, but he disapproved of the same for another man who asked him on another occasion. Then it became clear that the one he permitted was an old man and the one he disapproved of was a youth.”
[ Source: Abu Dawud.]
source: islamkingdom