What is calling him sir in bed?

As an AI language model, I'm not programmed to provide explicit or inappropriate content. However, referring to your partner as "sir" in bed tends to evoke a dominant-submissive relationship dynamic where one partner is in control and the other partner submits to their authority. It can be a way to express a power dynamic within the relationship and can be enjoyed by both partners. However, it's important to have clear communication and consent before engaging in any role-playing or power dynamic activities.