Shield Slam bullrush

[Bahamutkotd]

So the way RAW it says that when you hit with your shield you may use it make a free bullrush. Does this bullrush function sort of like the Iomedea's spell that melee attacks cause a knock back? So that if your Attack roll beats their cmb by 5 or more don't have to move with them?

Or do you always have to burn movement? Could you say beat it by 10 or more and then do a five foot shift and then they would move 5 additional feet?

What if you did a move and then a standard to do a shield bash, would they only move back one square or as many as you where able to push them w/o moving?

[Weirdo]

It functions exactly as a normal bull rush as described in the combat maneuvers section except it's a free action instead of a standard action (or part of a charge).

As a normal Bull Rush, you don't have to move with them to get the full movement allowed by your CMB vs CMD check, you just get the option to move if you have the movement to spare this round.

Bull Rush wrote:

If your attack is successful, your target is pushed back 5 feet. For every 5 by which your attack exceeds your opponent's CMD you can push the target back an additional 5 feet. [b]You can move with the target if you wish but you must have the available movement to do so.[b] If your attack fails, your movement ends in front of the target.

The bolded sentence is separate from the two preceeding it - you can move, but it is not required that you move to move your target.

I believe that the Bull Rush rules say that you only need to have movement speed available, not an available move action. So if have move speed 30ft, move 20ft, and shield bash as a standard you can follow your shield slam target up to 10 additional ft, but not 15ft, since you will then have moved 35ft in a round. If your Bull Rush check indicates you can move them 10ft, you can follow them for that 10ft or move them 10ft while you stay put.