Is it true that zina (fornication/adultery) is like inserting the kohl stick into the kohl pot? And does this mean that the مقدمات (preliminaries) of zina are not zina but a lesser sin? And is foreplay without penetration considered zina?

The fornication (zina) that necessitates the legal punishment (hadd) is the insertion of the penis into the vagina. The evidence for this is the story of Al-Aslami with the Prophet, peace and blessings be upon him, and the saying of Abu Hurairah: "Everything short of the kohl stick entering the kohl pot (i.e., penetration), but once it enters, that is zina." Anything less than that, such as touching, kissing, and foreplay without penetration, is considered a form of zina, based on the Prophet's saying, peace and blessings be upon him: "Indeed, Allah has decreed for the son of Adam his share of zina... So the zina of the eyes is looking, the zina of the tongue is speaking, and the soul wishes and desires, and the private parts either confirm that or deny it."