Before they made their Reading & Leeds debut, Cork's finest sat down with NME to tell us about the magic of the festival, rising up the ranks from playing to seven people in an Oslo basement to 40,000 with Fontaines D.C. at Finsbury Park, the deep connection to their fans, the rollercoaster year of debut album 'Masquerade' and plans for a darker follow-up inspired by electronica and black metal