Post Afghanistan. Maybe sometime shortly after he returns the knife? Humour me for the sappiness of this.
"I get it Deeks. You don't need to explain. But when you're ready, I'll be waiting." Kensi told him. His eyes spoke what his words couldn't - a deep, heartfelt thank you.
"But there's one catch." She said. "Until we sort this" she gestured between them "out, we need to take a step back. We keep movie nights, and we can keep spending the night. But nothing physical. Nothing intimate. No kissing." She told him. He sighed, but nodded in agreement. Kissing Kensi was one of the greatest joys of his life, but it wasn't fair to her if he wasn't ready for more.
Mid Season Six... before Humbug.
Kensi and Deeks were sprawled on her couch, take out containers on the coffee table, and neither had any intention of moving. The movie had ended, but neither moved to turn it off, letting it instead start over. Deeks rolled over to face Kensi, staring at her intently as their faces drew closer. She spoke first.
"Deeks, no. I told you, we can't do this if you're not ready for us to be... us." She gently pushed him away. He smiled, and instead drew himself close to her again. Her eyes met his, wondering what he was doing. They stared intently at each other, for what seemed like hours, before he slowly and gently closed the distance between them and his lips met hers. She jerked back.
"Deeks! I told you, no. We can't..." She paused as her brain processed what had happened. "Wait... are you, was that, I mean, are you saying?" Her confused babble was cut off as Deeks kissed her again, this time more deeply, as his hands came up and wound themselves in her hair. She started to kiss him back, timidly at first, then hungrily. When air became necessary, they pulled apart.
"So now, we're us." He finally said, before he leaned in to kiss her again.