Losing It

Written for the kinkmeme. Prompt: Back when Oikawa was under a tremendous amount of pressure and felt envious of Kageyama's skills in Kageyama's 1st year, Kageyama asked Oikawa for tips all the time. Instead of Iwaizumi rushing in to calm things down when Oikawa almost struck Kageyama, Iwaizumi is absent and fails to prevent Oikawa from losing it. WARNING: NON-CON