TAYLOR SWIFT COUNTERSUES RADIO DJ . .. YOU DEFINITELY GRABBED MY ASS

Taylor Swift just laid down the law . . . nobody grabs her ass and gets away with it . . . because she just countersued a radio DJ who claims she falsified a story about getting groped . According to the docs . . . Swift says she ' s 100% sure David Mueller lifted her skirt and grabbed her butt in 2013 at a backstage photo op for her Denver concert. As we previously reported . . . Mueller initially sued Swift . . . claiming he was fired from his radio gig after the singer claimed the radio jock groped her . Mueller now claims the assault was carried out by another guy . . . but in her docs , Taylor insists Mueller was the one who got handsy , leaving the singer, "surprised, upset , offended, and alarmed . " Taylor ' s asking for damages to be assessed by a jury , and says she ' ll be donating any money she wins to women ' s charities .