I don't remember much from this ficbut there is a scene that keeps running thru my head. Loki is staying with the Avengers in Stark tower and wakes up one morning and decides its been awhile since he'd been in female form and switches to Lady Loki before going down to breakfast. The avengers are obviously all surprised except for Thor who takes it as normal and changes seemlessly to female pronouns and sister.
That all I remember, it may have been FrostIron but i'm not 100% on that.
Hopefully someone knows it, has been driving me nuts