Alphonse's mother kissed him very often when he was young. She would kiss him on the cheek before sending him off to kindergarten, and catch his struggling brother for one, while their friends giggled. She would kiss him on the forehead when he did something that made her proud, like completing a good transmutation, or cleaning up his room without being asked. She kissed his scrapes when he hurt, and she kissed his lips before she tucked him into bed at night, and sometimes, as he helped her with the cooking, and got himself so covered in flour that his adorableness was utterly irresistable, she would pinch his chin, and kiss him on the nose, the only clean part on his face.
Being kissed by Wrath was not like being kissed by his Mother. He was surprised, at first, when the violet eyed boy who had normally been completely mean to him when they encountered each other on his visits to the Rockbells, had told him, with a profuse blush, that he wanted to go for a walk. He was shocked to have Wrath slip his automail hand into his own flesh hand, and stop beneath the plum tree in the backyard, where he could remember having played as a child, getting those scrapes that earned his mother's healing touch. He was almost a little scared by the foreign feeling of Wrath's lips pressed against his; he froze, his heart fluttering, and confusedly wondered exactly what had just happened. He felt apprehensive, worried, even a little bit ashamed; all things that felt alien to him; he'd never felt that when Mother kissed him.
Yet, there was a tiny hint of warmth he felt, as Wrath's hands held on to his. It was warmth; not physical, but a deep caring, a desire of belonging; and that was definitely something he knew of.
It was the first kiss, but one of many to follow.