Eidolon Grabbing and Constricting

Question

So designing a new Eidolon with tbe serpentine base form. Using such he qualifies for the Constrict evolution

An eidolon gains powerful muscles that allow it to crush those it grapples. Whenever the eidolon successfully grapples a foe using the grab evolution, it deals additional damage equal to the amount of damage dealt by the attack used by the grab evolution. This evolution is only available to eidolons of the serpentine form

My original question is this do you double the damage done by the original attack or do you reroll the original attack damage?

The reason i need this clarification is because of the Final Embrace feat tree, with Final Embrace Master stating

Benefit: Double the number of damage dice for your constrict special attack.

As a follow up bonus question. My Eidolon has 4 Natural Primary Claw attacks. Can he hit with a claw, grab the opponent dealing constrict damage. Drop the poor thing, than rinse and repeat the other 3 attacks? Or do i need to make the grab the last attack?

Answer 1

For your first question, the wording is clear: there is no reroll, and the additional damage dealt is the same as the original roll.

With the Final Embrace Master feat, you just double the number of original dices on your grab attack, but only if you decide to use constrict on that grab (so if you use a normal grab you only get to roll the original attack)

For the second one, tecnically they're all free actions:

Grab (Ex): An eidolon becomes adept at grappling foes, gaining the grab ability. [...] Whenever the eidolon makes a successful attack of the selected type, it can attempt a free combat maneuver check. If successful, the eidolon grapples the target. [...]

And

Grapple: As a standard action, you can attempt to grapple a foe, [...] Although both creatures have the grappled condition, you can, as the creature that initiated the grapple, release the grapple as a free action

so you can make a full-round attack, get your free grapple/break grapple checks and deal damage with every check. However, as for the free action type description, the DM has the last word on how many free actions you get during your round, so results may vary.

If you have difficulty imagining a creature with claws grappling an opponent multiple times, imagine a creature with tentacles instead, establishing a hold on different body parts and trying to crush each one.