Moralo talks about the Sheldon and Penny Kiss

Fans went bananas after the smooch, so we reached out to Steve Molaro, Executive Producer of The Big Bang Theory, who allowed us to pick his brain about this particularly unexpected puckering.
How did the scene come to be, and how long have you wanted it to happen?
Steve Molaro: We needed a scene to recap where we were in the rocky start to Leonard and Penny's marriage. Eventually, we landed on the dream sequence and hoped Sheldon and Penny making out would be an explosive start to the episode.
The first thing Kaley [Cuoco] asked me when she saw the script was, "How long have you been waiting for Penny and Sheldon to do this?" She already knew the answer was "Forever."
What was it like to shoot? How did the live audience react?
SM: The audience went insane. Jim [Parsons] and Kaley actually held the kiss a lot longer than what was on TV—and the audience was happy to scream until they stopped. It was an amazing moment and it set the tone for a really fun night on the stage. What's your response to the rabid fan reaction?
SM: I suppose my reaction is, "Cool! Who should we have make out next?" I'm so happy to hear the audience enjoyed it as much as we enjoyed shooting it.