Aubrey Plaza's deadpan humor never fails to get a laugh, and the hilarious story she recently told to Jimmy Kimmel about shooting a graphic *** scene with her Dirty Grandpa costar Robert De Niro was ** exception. After calling her ***-obsessed college coed character "terrifying," the actress went on to describe the pair's scene, which took a whopping nine hours to shoot. "There was a lot of interesting stuff that went down, you k**w," she said. "I'd try to get in there, and Suck on his nipples, and he was like batting me away, and I didn't k**w if it was in character or **t, because you never k**w with him." Watch the funny video above, then check out photos of Aubrey rocking a bikini on the movie's set!