What should I do for my repentance to be accepted, and how do I make up for my invalid prayers (Fajr prayer only) for which I performed tayammum out of fear of illness? And do I make them up at any time, or in the morning or at night? And do I make them up aloud or silently? And do I say the Iqamah for each prayer if I want to make up more than one prayer at a time?

Masturbation is a bad, forbidden habit. Tayammum (definition) is a concession that, according to many scholars, is not granted for sins. Some scholars, however, are of the view that if a sinner cannot use water, he may perform tayammum and pray, then repeat the prayer due to his negligence in not repenting. To make up for missed prayers, pray each day in addition to the five current prayers as much as you can, and continue doing so until you are certain or highly confident that you have made up for what you missed.