What is the ruling on practicing masturbation, exposing one's 'awrah to women in the street, sending pictures of it to them, or posting them on social media, and how does one repent from these actions?

These reprehensible and forbidden acts expose you to Allah's wrath and punishment. Hasten to sincere repentance, strive in supplication, reflect upon death and its terrors, upon Allah's attributes and His anger, associate with good people, frequent mosques, circles of remembrance (dhikr), and gatherings of knowledge, and distance yourself from forbidden provocations. Strive against your lower self, and Allah will guide you, as He says: "And those who strive for Us – We will surely guide them to Our ways."