Sakura
Everytime they land in a new world, Subaru can't help but look for Sakura trees. They were his favorite flowers even though Kamui hated them. Despite the fact that the Sakura was beautiful, they reminded Subaru of the one person he longed to see. The one person he loves and cares about more than anyone in the world besides his twin.
Kiss
The one thing that had started all of this was just one, simple kiss before they ran. Seishirou had remembered how those soft, velvet lips felt against his. They had been sweet and delicious. But after that, they ran before Seishirou could do anything. Now, he's traveling to find them while wondering how he can get Subaru to kiss him again.
Smile
Subaru always wondered why Seishirou smiled all the time. Especially at times when things get painful for the two of them. Sometimes, Subaru wished that Seishirou would show his true feelings instead of hiding behind a fake smile all the time.
Sweet
Seishirou had always liked sweet things. It was a secret weakness that no one but Subaru knew about. Subaru had told him that eating sweets would give him cavities but Seishirou had shrugged it off and kissed him instead. If Seishirou had to choose what was the most sweetest thing he had ever tasted, it would have to be his beloved Subby.