Two days ago, Essora gave Arabel a slave collar to put on Idan, her "toy", so as not to arouse suspicion while moving around the city.
Essora said it wasn't a real collar, but a fake one, but the couple immediately realized it was a lie.
And then Idan had a plan.
He decided to deliberately fall into the trap that Erza had prepared for them. Knowing almost everything she had prepared, Idan quickly assessed her possible options and shared them with Arabel.
Arabel was not thrilled with the proposed plan, but nevertheless, believing him, she agreed to support him.
When Arabel turned to hand Idan the collar, she deliberately blocked Essora's view.
Taking advantage of this, Idan imperceptibly replaced the collar with a new one, purchased in the trading function for 500 System points, almost indistinguishable in its appearance. He quickly hid the fake one inside the storage.
What followed was just an acting game that they played out in front of Erza to achieve what they wanted.