Peters was given a hospital gown to wear for a risque scene, in which Lange whips his bare bottom, for the first episode of the drama's second season.
Thinking he would be well-covered, the 25 year old dove right into the shoot, without realising he would be showing more skin than was required.
He tells New York Magazine, "It's embarrassing that I'm telling you this, but why not? I had to wear a c**k sock, right? And since I was wearing a hospital gown, I thought, well, my front's not going to be showing. It's not a big deal. And when they bent me over they could see my b**ls hanging down from the other side. The first day of shooting, and I flash Jessica Lange and Sarah Paulson my b**ls. Welcome to American Horror Story. It was ridiculous."
But the actor insists he's glad his wardrobe malfunction happened because it helped break the ice and bring the cast together.
He adds, "Once someone's seen your b**ls, it's over. It's fine. Everything's good. They didn't even say anything. Sarah just walked over after that take and kissed me on the cheek. I was like, 'Why? What's happening?' That's when I realised. I was mortified."