I tried demerol, and I waited till around 40-45 % to start focusing at all...
I turned on the full panel visualization (I highly reccomend it).
I watched it for seemed what hours. My body was heavy and every now and then I would get a rush of euphoria. It was almost so intense I had to stop.
The visualizations do help... believe it or not.. you start to see weird patterns (Like a rabbit constantly hopping in place, or diamonds streaming by..)
Hit all the pleasure centers... lasted about hour and a half..