Shadow Blend?

[Whiplord]

I'm confused as to how exactly this should work. I made a search and wasn't able to come up with satisfactory answers.

My main questions are, what kind of action is it, and is it affected by darkvision? My gut is that darkvision doesn't matter since it's not based on a Hide check, and is a supernatural abiility, but I'm unsure.

Is there any sort of ruling on this?

[Biffoniacus_Furiou]

Shadow Blend (Su): In any conditions other than full
daylight, a shadow creature can disappear into the shadows,
giving it total concealment. Artificial illumination, even a
light or continual flame spell, does not negate this ability, but a
daylight spell will.

I doubt it would take any action at all to activate, just say it's always turned on. In the daylight the ability is suppressed, but once you get into the shade your form becomes indiscernible and nobody can even tell exactly where you're at. Any ability to see through darkness, such as Darkvision, probably wouldn't even be able to see through it even if they can see through the darkness that grants it.

One good trick is to wear a small mundane pendant and get a Deeper Darkness cast on it every few days. Hold it in your mouth so that its effect is blocked, but you can 'drop' it as a free action at any time by spitting it out, thus plunging the area into darkness which you immediately disappear into.