Sylvain grins at the sound of that laugh, sharp pleasure warming golden eyes with pleasure and satisfaction that he'd caused that. It wasn't a sound he heard often from Kaz, despite everything, so he cherished the ones he did get to hear.

With the vow spoken into the universe, binding Kaz to his word, his smile softens a little and he draws the other man back in for a kiss. Slower, this time. More deliberate. Lazy, almost. Apparently they had a whole day and night to explore this now - something he was going to take full advantage of.

"Well said." He murmurs against Kaz's lips, before he gives the other man a playful smack on the ass and tugs him back down the street again. "Now we have a party to get to and we shouldn't be late."