In Hindu traditions, there has been a lot of talk on the concept of "MahaSamadhi" and I have heard of various personalities leaving their body("Dying" as per me) as per their will. I have been very curious on this subject. In general, the illusion of life has designed itself in such a way that death is either painful or with suffering. As per the understanding I have, "MahaSamadhi" is a way of meditating and controlling body vitals in such a way that the body dies without any suffering.

I would be very happy if anyone has any more information on this or knows steps or path that can be practiced that can result in "MahaSamadhi". So basically, it would be really helpful if I gain any information on this and can progress on this.

Please note, I do not have any suicidal thoughts or I am not in any sort of depression. I have made small progress in mediatation and I am leading a contented life with as much equanimity as possible. The current post is just a child of my curiosity and it would be good if I can decide and die at my chosen time in future.

I noticed myself tagged in this thread, so will respond this time.

I know a number of advanced meditation teachers who have died, but, having not died in this life yet, I have little knowledge of this for myself.

I also have yet to witness the death of an advanced meditation practitioner for myself, so also don't have that second-hand knowledge either.

I do know as a physician that what we often call "comfort care", meaning adding anti-anxiety and anti-pain medications such as ativan and morphine, do seem to effectively provide what you are looking for, but clearly that is not what you asked.

Apologies for my ignorance on this.

Remarkable death stories of advanced meditation practitioners are common, the main ones that come to mind are rainbow body and tukdam in the Tibetan tradition, both of which seem to be reliably witnessed.  The attainment of these states is often framed in the context of a specific practice, as you noted, but I think this is misleading.  The reality most likely is that these are simply occurrences that are only available to individuals with very high levels of meditative realization, and even then are likely not entirely controllable.  

I very much doubt that any master would chose to die at a certain time, more likely they would simply have a greatly heightened awareness for when death is approaching, and for any subtle stages of transition that might occur.  If you desire such an experience, I would advise you to aim high in meditation.  However, striving for advanced attainment might be better approached with an attitude of reducing suffering in this life, versus gaining control over ending it.

Actually, in my clinical practice I have known people who were not meditators who seemed to choose the time of their death. The common scenario is an older long-term married couple in which one dies and then, typically within a day or two, the other decides to join them in death and simply dies. I don't mean suicide in the sense of taking pills or something like that, I mean someone who just somehow simply makes the choice to die and they do. Thus, I do believe that dying in this way is possible, having seen it for myself.