Can a serpentine eidolon use multiple natural attacks while grappling?

Question

Can a summoner's serpentine eidolon with bite and 2 tails with tail slap(3 natural attacks) attack with both bite and 1 tail slam after it has grappled an opponent? The grappling rule states:

Damage: You can inflict damage to your target equal to your unarmed strike, a natural attack, or an attack made with armor spikes or a light or one handed weapon.

I'm stuck on "A natural attack". Does that mean you can only use a single natural attack while grappling? It seems like one of the eidolon's tails would be used for the grapple, but the other tail could still tail slam as a secondary attack and bite as a primary attack.

Answer 1

No, it can't. Your reading is correct. The RAW is consistent here in using the singular, and what's more it doesn't say that you actually make any of those attacks in the usual way (because you don't): rather, you "inflict damage" in the amount of one of those options. It's not meaningful to "inflict damage equal to" multiple natural weapons.

From the standpoint of rationale and balance, it requires a standard action each round to maintain the grapple. Making multiple attacks as a standard action is not generally possible, and maintaining a grapple requires actively working against someone who would generally rather not be in it, so it's fitting that grapple not permit multiple attacks. Put another way, if it normally requires all your effort/focus for a round (full-round action) to use all those natural attacks together, how would it make sense to require less effort to do all that and also hold someone in place?