How does Swordmaster's Shirt (Melee Tactics Toolbox) work?

[Sergeek The Mad]

So there is this bodyslot item from Melee Tactics Toolbox, page 29:

Swordmaster's Shirt wrote:

This stylish silk shirt has a loose and flowing fit except for the sleeves, which cling snugly to the wearer’s arms from elbow to wrist. The sleeves guide the wearer’s attacks to take advantage of brief gaps in a foe’s defenses. Five times per day, the wearer can make a lunging melee maneuver and extend his reach by 5 feet for a single melee attack. If the wearer has the Lunge feat, he can instead use that feat five times per day without taking the normal –2 penalty.

So how do I make this maneuver? What kind of action do I spend? Can I use it for attacks of opportunity?

[Kalindlara]

It's made as part of the attack, at no action cost.

You can't use it for attacks of opportunity because you don't threaten those spaces.

[CampinCarl9127]

It's a free action, it costs you nothing. The ability only gives you reach for the attack in which you use it for, so you cannot take attacks of opportunity with the extended reach.

[Sergeek The Mad]

I see, thank you.
I was thinking about doing it with Come and Get Me, to avoid enemies 5-stepping out of my reach before attacking me, but oh well.