Hi guys, I have a questions about Armor spikes
Armor Spikes: You can have spikes added to your armor, which allow you to deal extra piercing damage (see "spiked armor" on Table: Weapons) on a successful grapple attack. You can also make a regular melee attack (or off-hand attack) with the spikes, and they count as a light weapon in this case.
Is that working like Constrict when Grapple? will deals extra piercing damage every time when I makes a successful grapple?
It just means you can use them for the "damage" option in the grapple rules: "Once you are grappling an opponent, a successful check allows you to continue grappling the foe, and also allows you to perform one of the following actions (as part of the standard action spent to maintain the grapple). (...) 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. This damage can be either lethal or nonlethal." CRB pg. 200