You've got the wrong conjunction, the one you were looking for was "and".
[He can tell she's laughing at him, but because it's Kanaya rather than making him more grouchy this gives him the tiniest inkling that he's being ridiculous--which he ignores, because fuck acting reasonable.]
no subject
[He can tell she's laughing at him, but because it's Kanaya rather than making him more grouchy this gives him the tiniest inkling that he's being ridiculous--which he ignores, because fuck acting reasonable.]