My kingdom for just the sluttiest most eager most enthusiastic Omega Gladio, gets excited for his heat coming on like a kid at Christmas because being desperate and filthy and out of his mind for his Alpha(s).

+ or maybe what gets him that excited is his Alpha(s) going into rut, when he's NOT out of his mind and can savor every second of being fucked and filled over and over again.
++ Gladio won't shower or bathe unless Ignis (and/or the other two) force him because he loves how filthy he gets
+++ They'd never risk a pregnancy on the road, on the run like this, but it doesn't mean Gladio doesn't want to hear how badly they want to breed him