Final answer:
Uma's death was likely caused by autoerotic asphyxiation, a high-risk sexual behavior that involves restricting oxygen to the brain for sexual arousal.
Step-by-step explanation:
Based on the tragic scenario described, the practice that most likely caused Uma's death is autoerotic asphyxiation. This involves intentionally restricting oxygen to the brain for sexual arousal, but it is highly dangerous and can lead to accidental death, as it seems to have occurred in this case. It's important to note that such practices should always be conducted with the utmost care and awareness of risks, and in this unfortunate instance, safety measures were not sufficient.