In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Masturbation is a major sin and an evil habit which should be abandoned. You should bear in mind that Allah sees all things even those that are done in darkness and in privacy. Fear Allah and do not commit sins as that incurs the anger of Allah.
It is stated in العناية شرح الهداية (Inayah - Sharah Hidayah) that Rasulullah Salallahu Alaihi wa Salam cursed the one that is married to his hands, that is the one who masturbates.[1]
Rasulullah Salallahu Alaihi wa Sallam said that one should fast to suppress his carnal desires until he/she is able to get married.[2]
Ghusl will become compulsory on one who masturbates and semen is discharged. (Bahishti Zewar Vol. 1 Pg 72).
You cannot simply wear clean clothes after discharging. You should first make ghusl then wear clean clothes.
And Allah Ta’āla Knows Best
Mufti Saeed Ahmed Golaub
Islamic Solutions
Jamaica
References
[1]:وَهَلْ يَحِلُّ لَهُ أَنْ يَفْعَلَ ذَلِكَ إنْ أَرَادَ الشَّهْوَةَ؟ لَا يَحِلُّ لِقَوْلِهِ - عَلَيْهِ الصَّلَاةُ وَالسَّلَامُ - «نَاكِحُ الْيَدِ مَلْعُونٌ وَإِنْ أَرَادَ تَسْكِينَ مَا بِهِ مِنْ الشَّهْوَةِ أَرْجُو أَنْ لَا يَكُونَ عَلَيْهِ وَبَالٌ» العناية شرح الهداية (2 / 330)
[2]:1905 - حَدَّثَنَا عَبْدَانُ، عَنْ أَبِي حَمْزَةَ، عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، قَالَ: بَيْنَا أَنَا أَمْشِي، مَعَ عَبْدِ اللَّهِ رَضِيَ اللَّهُ عَنْهُ، فَقَالَ: كُنَّا مَعَ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ، فَقَالَ: «مَنِ اسْتَطَاعَ البَاءَةَ فَلْيَتَزَوَّجْ، فَإِنَّهُ أَغَضُّ لِلْبَصَرِ، وَأَحْصَنُ لِلْفَرْجِ، وَمَنْ لَمْ يَسْتَطِعْ فَعَلَيْهِ بِالصَّوْمِ، فَإِنَّهُ لَهُ وِجَاءٌ» صحيح البخاري (3 / 26)