Me and my friend would smoke from his bong almost every night. We would smoke until both of us were thoroughly stoned and then play some video games. After the peak we would go back and smoke until there was no question we were blazed again. What I find is that when you go back for more, you CAN smoke enough to experiance a peak again. But it is almost never as intense as the first and it just decreases as you continue to go for more. The only way I would ever get that same first peak was to fall asleep and smoke again.