I'm honestly not sure I understand the question.
Having said that, here's my algorithm.
While point shooting, I pull said shotgun
tightly into my shoulder
while allowing the fore end to
rest in my left hand.
Upon squeezing the trigger, I'm pulling ever so slightly backwards on the fore end, such that immediately after trigger pull, said fore end comes back with a force equivalent to a nuclear reaction, only to get pushed forward again (after reaching the end of backward travel) with equal force, jamming the next cartridge into the pipe.
This entire pump action requires about 1/4 sec or less.
Caveat emptor: make sure to keep your left hand well up on the fore end
to prevent your "pinkie" from getting pinched between the fore end and receiver.
(In general, that only happens once, twice at most.)
Nem