AFTER 10 long years, Madonna and Kevin Costner FINALLY buried the hatchet — not in each other’s skulls! — ending a nasty feud that started when she stuck a finger down her throat on-camera to show the world that Kevin made her “BARF”! The outrageous scene was lensed on her “Truth or Dare” video and showed nice-guy Costner showing up backstage to congratulate Madonna after a show. For some bizarre reason, the kinky diva took offense when Costner gushed that her performance was “neat”! As Costner turned to go, Madonna threw a shocking tantrum behind his back — sticking her finger down her throat and making vomitous sounds. Then she said into the camera, “Anyone who says my show is ‘neat’ has to go!” Costner was FURIOUS when he saw Madonna backstab him on the video and the two NEVER spoke again! But time heals all wounds and when Costner’s kids begged to see Madonna’s LA concert he bought tickets. Madonna spotted his name on the V.I.P. list and stunned him by dedicating the song “Secret” to him onstage. After the show, Madonna invited him to her dressing room, gushed over his kids — and apologized for her nauseating behavior.