What is the ruling on a man and woman who kiss, and do everything else other than intercourse?
Answer: These deeds which you have mentioned are impermissible – unlawful for them, because Allah – the Most High – says:
And those who guard their chastity (i.e. private parts, from illegal sexual acts) except from their wives or that their right hands possess, for then, they are free from blame, but whoever seeks beyond that, then those are the transgressors;
And His statement – The One free from all deficiency, the Most High:
And come not near to the unlawful sexual intercourse. Verily, it is a Fahishah [i.e. anything that transgresses its limits (a great sin)], and an evil way (that leads one to Hell unless Allah forgives him).
And Allaah did not say, “And do not fornicate”, except to deal with everything that is a cause and leads to fornication, and this – what they are doing – is zina of the hand by touching, zina of the eye by looking, zina of the feet by walking (to do that which is haraam). This is impermissible for them and it is obligated on them to repent.
It is obligated on those given responsibility to educate them and dissuade them from the likes of these actions, and turn them away from this sin.
The Messenger of Allah (sallallaahu alaihi wa sallam) did not prohibit a person from being alone with a strange woman (one who it is not permissible to be alone with) except out fearing this this deed and its likes.
So you, may Allah give you success, advise them with that which is obligated on you, warn them about this, the impermissiblity of this is clear and is present in the books of tafseer, books of hadeeth, books of fiqh, all of them. It is not allowed and it is impermissible.
Fataawa Noor Alad Darb Vol 5. Page 549. Slightly paraphrased