Going through my files and stuff...
I'm not sure the exact positioning (only did it 3 times at the spot I'm going to mention), and it was realllllly wonky (decayed, showed up at the tower, and auto-decayed to Lorminstra's altar; didn't lose XP; etc) in each attempt..
..but if you die at the altar of Luukos on Teras..
The experience is MUCH different than dying regularly.
Decaying is different too...
..because it's an easy to do 'secret', I'm not going to openly spoil it.
I've attached my dual decay log if you just want to read it.