Enzo was the one who knew Damon inside and out at the most basic levels. He had seen the real man, and Damon thought he saw Enzo as well. There was no reason to hide anything, at least not in there. Enzo was one of the only people that Damon truly trusted. Leaving had broken him. Having him back was something he couldn't explain yet, but it was waking up fast.
Damon got the response he was looking for, a firm acknowledgement of something they had both wanted for years. Damon growled softly into the kiss, absorbing all of the heat, returning it. One hand wrapped around Enzo's neck, and the other found purchase in his shirt, pulling as much as Enzo pushed him. He had imagined this so often when they were separated by the bars. Determined not to let go, his grip tightened by instinct.