Hope you are fine and enjoying the blessings of Allah Almighty. Here I want to ask a question about the atonement (Kaffāra) of Fast. My Question is that can a boy and a girl who are unmarried kiss and lie together during fast? What if they touch private parts? What will be the punishment and atonement (Kaffāra) of such acts?
Fast is broken if someone enters sexual intercourse, eats or drinks. Any act that is intended to arouse and satisfy sexual gratification is included in sex. We are talking about sexual relations with legitimate life partners. Therefore, kissing and foreplay invalidates the fast even when carried out by married couple. This act committed by unrelated male and female adds other sins to breaking the fast.
Then there is also the essence of the worship ritual. The spirit of the fast is not to stay hungry. It demands the sense of worship alive in one. It would therefore not be possible for one to engage in acts which negate and confront the very foundation of the worship. Therefore, we can say that people going as far as oral sex and foreplay should not be considered engaged in the worship ritual at the same time. They should make up for the fast if they intend to repent.