In your private quarters, you can change your hairstyle or bond with your allies.
When bonding with units, units whose portraits have a small heart next to them will gain actual support points if you bond with them. Units whose portraits do not have the small heart will not gain any support points, but you’ll still get fun dialogue from them nonetheless. Once you have achieved A rank with someone, you’ll start building more hearts and getting some other special bits of dialogue.
Once your Avatar gets married, their spouse will move in with them and reside in the Private Quarters with you! From then on, you have access to the Bond option, which lets you view special lovers scenes with them. You’ll also get unique dialogue you can’t get just from plain old bonding.