Author:https://archiveofourown.org/users/hotpinklipgloss/pseuds/hotpinklipgloss Soucre: https://archiveofourown.org/works/9636422 Summary: "It takes what feels like ages for Oikawa to process that yes, Kageyama is an omega, yes he is going into his first heat in the middle of a practice game, and yes Oikawa is already half-hard in his shorts just from a few whiffs of Kageyama's scent." Or how Kageyama's and Oikawa's relationship progresses through Kageyama's heats.