When is the Hadd punishment for adultery applied to a servant: Is it applied when the two circumcised parts meet, or if intercourse occurs externally (ejaculation outside the womb), or is it only applied with complete penetration?

For the Hadd (prescribed punishment) ofzina to be established, it is required for the entire glans of the penis to be inserted into the vagina, regardless of whether ejaculation occurs or not, and whether the penis is erect or not. This does not imply leniency regarding other prohibitions. A man being alone with a non-mahram woman (khalwa), touching her, and kissing her are all forbidden, and a Muslim must abandon these acts out of fear of Allah's punishment.