In Islamic jurisprudence (Fiqh), the majority of scholars agree that any form of sexual activity, including masturbation, invalidates the fast, regardless of whether ejaculation occurs or not. The act of masturbation is seen as a physical and psychological stimulation that may lead to ejaculation or disrupt one’s state of fasting, and it goes against the principles of self-control and purity that fasting is meant to uphold. It’s essential to maintain the sanctity of the fast during the daylight hours of Ramadan or any other fasting day, refraining from all forms of sexual activity and other actions that break the fast. If someone intentionally engages in sexual activity or masturbation during fasting hours, their fast is considered invalid, and they are required to make up for that day by fasting another day after Ramadan. It’s important to seek guidance from a knowledgeable Islamic scholar or religious authority if you have specific questions or concerns about fasting and its rules, as interpretations may vary among scholars and schools of thought.