Just in case you haven't seen all of them:
I've seen some many antis insist that they're father and son, they're not kissing here, Sebastian is actually just trying to eat his soul! Except none of them ever mention that this is demon!Ciel, and he no longer has a soul to take.
Also, a couple more official arts for your perusal:
The controversial 'hickey' art, which was drawn by Yana herself. (For a kuro perfume line advertisement, iirc. You can see Sebastian applying it to his neck. Someone else made a tumblr post where they bought that very perfume to try themself, and it went on clear)
Yana's contribution to kuro's 19th anniversary. (This is not the whole picture. Also, in Japan, sunflowers represent true love, and are associated with the phrase, 'looking only at you', for the way sunflowers track the sun across the sky throughout the day. The specific number of sunflowers can also have their own meanings)
Plus Yana's mimosa art (the yellow flowers in Ciel's hat are mimosa, which can represent hidden or secret love. And as we know, Sebastian dresses Ciel to his preference)
I've seen the one where they're literally about to kiss before but not the second demon ciel one?? why does it look like they just got married
I LOVE the 19th anniversary art!! it feels so soft and warm and the way they look at each other makes me insane. sebastian especially looks soooo in love. no wonder the "only looking at you" flowers were used
I somehow don't think I've ever seen the original mimosa art, just fanart. I love when yana puts ciel in giant beautiful extravagant hats and coats and half-dresses and then sebastian just has like a pocket square or something. they're like those straight celebrity couples at the met gala where the men give absolutely nothing