Nightfall in men is a natural process where semen is involuntarily discharged during sleep. It is also known as "swapandosh" in Hindi. Nightfall is a common occurrence in adolescent boys and young men, and it usually decreases as they age. Some common causes of nightfall include:

• Sexual arousal during sleep
• Lack of sexual activity
• Overactive imagination
• Stress and anxiety
• Certain medications

There are several home remedies that can help prevent nightfall, such as drinking a glass of warm milk before bed, practicing relaxation techniques like yoga and meditation, and avoiding spicy and fried foods. It is important to note that nightfall is a normal bodily function and does not usually require medical treatment. However, if it is causing distress or interfering with daily life, it is recommended to consult a healthcare professional.