In the Name of Allah, the All-Merciful, the Mercy-Giving

All praise is due to Allah. Peace and blessings be upon His Messenger Muhammad.

“Say: “My Lord has only forbidden indecencies, whether open or secret; and sin, and unjust oppression; and your associating with God anything for which no authority has been revealed; and your saying of God what you do not know.” (Al-A`raf 7:33)

When the Prophet (peace be upon him) was asked to define sin, he said, “Sin is that which agitates your mind, and you are ashamed of people watching you when you do it.” (Al-Bukhari)

Masturbation is a sinful act, and the fact that you do it in private proves that you consider it as shameful.

If, on the other hand, you are doing it in public, it is worse, for it shows that you have no shame; furthermore, if you did it in front of public believing it to be to as lawful ethers that would be an act of kufr.

According to Islamic teachings, if a person declared as lawful that which Allah has made unlawful he or she may go out of the fold of Islam.

Having said this, I would urge you to seek repentance for your sins. I pray to Allah to make us cherish faith and love the deeds that enhance it, and make us abhor and detest disbelief and sinful actions, both open and secret, outward and inward.

Almighty Allah knows best.