Damon knew that Elena hadn't intended to fall in love with him. She had been clear in the fact that she loved Stefan, that it would always be Stefan and that she cared about him, but they could never be together the way that Damon longed for them to be.
He still remembered the pain of seeing her with Stefan. Of watching her love his brother the way that he knew that Katherine had loved Stefan and he had questioned what was wrong with him that he was unlovable. That he wasn't capable of the affection that his brother had. Everyone loved Stefan and he had been kept alive mostly because of the fact that he was Stefan's brother.
But somewhere along the way that had changed. Elena had changed him. She had made him feel emotions that he hadn't felt in such a long time. She had flipped his switch back on and he was grateful to her for that. Even if she had made him feel pain at first, it was all worth it to get to this moment in time with her.
Elena was, corny as it sounded, the most precious thing in Damon's world. He would always do whatever it took to keep her safe, risking his own life and the lives of everyone around them to do so without an afterthought.
Effie was the last thing on Damon's mind right now, which he knew was bad of him but he couldn't help the fact that Elena's presence was intoxicating and completely distracting to him and he couldn't get enough of her now that he was allowed to have her.
He looked up at her at her question. "Yes, we are," he said, smirking at her. "Why, Elena, are you planning to seduce me?" he asked. "Because I have no problem with that," he said, his smirk growing on his face.