Dreams involving intimate moments with a partner, especially in familiar or nostalgic settings, can reflect various aspects of your emotions and relationships. Here are a few interpretations to consider:

1. Desire for Connection: The dream may indicate a strong desire for intimacy and connection with your girlfriend, symbolizing your affection and passion for her.
2. Nostalgia: Being in a past buddy’s house could represent nostalgia or a desire to reconnect with a part of your past. It might signify that you are reflecting on old friendships and how they influence your current relationships.
3. Exploring Relationships: The dream could also suggest that you are exploring your feelings about your current relationship and your comfort level with intimacy. It may highlight your thoughts about how your past influences your present.
4. Social Dynamics: The setting of a birthday party may indicate social interactions and how you navigate relationships with friends alongside your romantic life. It may also reflect feelings about how your personal life intersects with your social circles.

Consider how these themes resonate with your current life and emotions. Dreams often serve as a way to process feelings and experiences, so reflecting on your relationship and its dynamics can provide valuable insights.