What is the ruling on doubting whether something discharged is semen or pre-seminal fluid, knowing that the act takes place inside the clothing? And what is the ruling on obsessive doubt regarding the impurity of everything touched by one's clothes during sleep? And what is the ruling on the purity of the hand if something from the discharge gets on it and it is then only washed?

The description of manī (seminal fluid) is well-known: it is a thick liquid with an odor resembling dough, which is ejaculated with pleasure in spurts. It is considered pure according to the preponderant opinion and necessitates ghusl (ritual bath). As for madhī (pre-seminal fluid), it is a thin liquid that exits without desire, and its exit is not followed by fatigue. It necessitates purification and wudūʾ (ablution). It is most likely that what exits during masturbation is manī. If this is the case, ghusl becomes obligatory, and there is no need to purify what it touches. When in doubt about whether the exiting fluid is manī or madhī, you may choose and assign it the ruling of one of them. Repentance from the forbidden act of masturbation is obligatory.