Are the preliminaries to sodomy in terms of their prohibition and sinfulness the same as sodomy itself? And is it obligatory to inform those who have been trespassed against about this so that Allah may accept repentance?

The preludes to sodomy do not reach the great obscenity (fahisha), but they are forbidden. Ibn al-Hajj al-Maliki mentioned that sodomy has stages: enjoying the sight, which is forbidden, and enjoying playing and embracing without committing the major obscenity. He believes that persisting in these preludes elevates them to the level of the major obscenity because "there is no minor sin with persistence." The repentant person must seek forgiveness from those with whom he committed the obscenity of sodomy in general terms without explicit declaration, as that would incite evil.