During orgasm, you don't magically create new nerve endings. It is the brain which amplifies the sensations when the brain has decided it was time to reach orgasm.
Prior to the snip, your brain was used to a certain movenent/cadence/sensation to decide how/when to trigger orgasm. This has changed and you/your brain has to relearn this.
As semi cut, I still J/o by moving skin up/down with skin going over part of glans on upstroke.
After firts fiull circ, the skin was still loose enough to move/up down, but stopped at rim on upstroke.
Force of habit/instinct got me to continue to move skin up/down, but found Iorgasm took longer and less intence. I then conscously tried to rub skin, but as I neared the point of no return, the brain took over wand wanted to switc to move skin uyp/down and that broke the orgasm and I have to restart from scratch.
It took a few weeks, but eventually managed a proper circumcised make j/o without moving skin and the orgasm was magnificient. Haven't looked back since. (and now, for the last few months, I became addicted to lube).
Anothe think you may notice is that the orgasm itself can last longer before the sensitivity causes you to want to stop and this may extend a bit beyond the last spurt.