>>527205202
It's Himeru's arm to the left and zenraman's elbow, bent, to the right. Kind of a weird clothing fold on zenraman's shirt, not sure what part of that is actually his elbow.
It's from https://litter.catbox.moe/jlqn59re6fkl567i.jpg (h-scene from the currently untranslated yamagishi apendo)