My setting is just like the real world, except for a twisted Excess God. Who demands rituals to exacerbate its Worshipers feelings, which he in turn feeds on.
There's just a problem, these rituals are supposed to go on for Days at a time, some of them are torture, the others are pleasurable.
For pleasurable ones to go on for days, other members will give them stimulants to be able to keep up without any sleep, norepinephrine if they start slowing down or not being in the mood, Beta blockers if hearth rate gets dangerous to prevent people from having hearth attacks to prevent death from happening until the end of the festival. This much I think I've figured out. They even use some external apparatus to do some of the work.
What can I do to keep the body from going into shock and conscious while causing excruciating pain for days, with current day technology ?
Bonus points if as soon as we stop what we are doing, they just drop dead. Even more, if they can be kept alive, disemboweled.