He's simply proud of himself for accomplishing the dip without making a fool out of himself or even worse making fools out of the both of them. The kiss isn't a reward as he gets them often enough but it certainly has that feel to it. Matthieu smiles, "You're really laying the compliments thick tonight. Pretty sure no one would argue with you cause well it's you saying it all."

Heat hits his cheeks and he presses one against Lucifer's shoulder while trying to fit the mild embarrassment. "Oh um I mean sure yea. You definitely enjoy that yup."