Forum:Once per turn, during either player's turn?

I'm getting confused on card effects that say 'Once per turn, during either player's turn'. (i.e. Legendary Six Samurai Shi En: Once per turn, during either player's turn, when your opponent activates a Spell/Trap Card: You can negate the activation, and if you do, destroy it.)

If a card says this, does it mean that the effect can be used consecutively between each of our turns? Meaning can my opponent use Shi En's effect to stop a trap card I try to use on their turn, end their turn, and then stop a spell card I try to use on my turn? Or do they have to wait?--December31 (talk • contribs) 00:44, July 11, 2013 (UTC)