Robert Irwin and Witney Carson are sharing secrets behind their Dancing With the Stars rehearsals. "I don't feel like I'm a drill sergeant, but we definitely work really hard," Carson, 31, shared on the Wednesday, October 15, episode of "The Viall Files" podcast. "We laugh a lot, but we definitely get stuff done. You have to. You only have four hours a day. You have to learn an entire new dance by Tuesday." With such limited time, Irwin, 21, joked that he gets creative in making the most of those four special hours.