“Not only does [the episode] ‘Mac Finds His Pride’ contain heartfelt dialogue — like Mac admitting to Frank, ‘I don’t know where I fit in as a gay man and it’s starting to get to me. I’m not feeling very proud.’ — but it ends with a five-minute, show-stopping contemporary-dance number featuring Rob McElhenney and professional ballerina Kylie Shea.” Here’s the inside story of how McElhenney, who insists to this day that he cannot dance, pulled it off.