I guess you're supposed to wait until rigor mortis sets in.
Rigor sets in and leaves depending on the ambient temperature. Warmer the body the faster the process, so the 6 hour time limit.
In Egypt a HOT country rigor can set in as soon as one hour and be gone in another 1-2 hours. Have to get to the corpse fast after the rigor leaves as once rigor is gone the body builds up gas and nasty stuff starts to happen.
Seems perfectly reasonable to set the time limit, at the correct time after rigor leaves, the body is plyable and easy to manipulate, has not yet begun to decompose and still has no [over coming ] smell.
Amazing the science that has gone into making this a law, almost split timing to gage the correct time to have sex with the dead.
Who can be surprised that a culture that once were leaders of the world in science and arts, sex maniacs, and have fallen into the promiss for the males of eternal sex with virgins after death would not find way to with science find a way to keep sex going on with the dead while alive on earth.
Most interesting culture, BUT, we must not question it, we must understand and emphasise with their laws and traditions. Who are we to question the lifestyle of others ?????
How much crazier can the world get, lets all jump on a boat with a tour group and watch some tribe throw virgins in a volcano for religious reasons. Totally raciest to not understand or except their life style.
