Does thinking and imagining that lead to arousal and the release of fluid necessitate ghusl? And can semen be released by mere thinking? What is the consequence for past prayers performed in this state? And how can one distinguish between madhy, maniy, and normal secretions?

What exits with desire is either mani (seminal fluid) or madhi (pre-seminal fluid). A woman's mani is thin and yellowish, and it may become white. Its smell is like that of a man's mani, accompanied by pleasure and followed by relaxation. Madhi is a thin, sticky, white fluid that exits with desire but without gushing or relaxation. Both men and women experience it.

If what exits is mani, then ghusl (ritual bath) is obligatory, even if it delays beyond the moment of desire, based on the Prophet's (peace be upon him) saying: "Water is from water." If it is madhi, then only wudu' (ablution) is required after purifying the exit point and whatever touched the body and clothes.

When in doubt between mani and madhi, the accountable person has the choice between their respective rulings; for example, they may perform ghusl or wudu'. If mani exits merely by thinking or taking pleasure in thoughts of intercourse, ghusl becomes obligatory. As for prayers performed without ghusl while janabah (state of ritual impurity requiring ghusl) was present, they must be repeated.