A behind-the-scenes photo reveals what it was really like filming Leonard and Penny's sex dungeon scene. Despite being grounded in reality, didn't shy away from fantastical elements in its storytelling. Sheldon's dreams in particular were vivid, despite how ridiculous some of them were. One of his most memorable night visions, however, involved his closest friends engaging in an intimate act.

As the inaugural couple of , Penny and Leonard shared a lot of intimate moments together, but there's nothing that compares to their sex dungeon scene. (via ) releases a new set photo of what it was like for Johnny Galecki and Kaley Cuoco to film that sequence, and it looks like the actors had fun with the out-of-character moment.

What Penny & Leonard’s Sex Dungeon Scene Was Really About

Penny and Leonard's dungeon scene took place in season 10, episode 7, "The Veracity Elasticity," in which Pasadena gang were helping Sheldon slowly cope with the change around him. While he was already living with Amy in Apartment 4B, he wanted to keep his old room as it was. However, everyone was trying to make him understand that once he no longer paid for rent in his former flat, the Hoftstadters were free to do whatever they wanted with his room, resulting in Sheldon's nightmare about it becoming a sex dungeon.

There was no indication that Penny and Leonard were planning on doing that. However, Sheldon's difficulty navigating intimacy, coupled with his inability to easily adapt, manifested into his specific dream about his friends' sex dungeon. What made it worse was that he treated his bedroom as a sanctuary for more than a decade, and he didn't like the idea that it was going to be turned into something very different from its original function.

It has been four years since . However, it remains very popular thanks to constant reruns on TV and streaming availability. New fun tidbits like this behind-the-scenes image are expected to help it maintain its relevance, despite the changing TV comedy landscape.

Source: The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series (via )