Dreams about police and authority figures often symbolize a desire for protection or a sense of security in your waking life. In your dream, you seem to be navigating a complex situation involving danger, safety, and relationships. Here are some insights into the various elements of your dream:

1. Police and Protection: The presence of police suggests a need for safety or a desire for someone to take charge in a difficult situation. You may be feeling vulnerable or threatened in some aspect of your life, and your subconscious is expressing a desire for support.
2. Handcuffs and Sexual Fantasies: Your request for handcuffs indicates a mix of wanting to feel both protected and perhaps exploring themes of control and submission in a safe context. This part of the dream suggests a playful exploration of boundaries and desires.
3. The Ex-Girlfriend: The appearance of the girl you are no longer friends with might suggest unresolved feelings or conflicts from that relationship. Her presence could symbolize past connections that still linger in your mind, possibly representing feelings of betrayal or competition.
4. Vampire Figure: The vampire ex symbolizes a threat or an emotional danger that could drain your energy or vitality. Protecting the police officer indicates a sense of loyalty and a willingness to fight for those you care about, but being bitten could reflect fears of getting hurt in the process or being overwhelmed by past issues.

Overall, your dream seems to highlight themes of protection, vulnerability, and the complexities of relationships. It might be helpful to reflect on any current situations in your life where you feel you need protection or where past relationships are influencing your present. Engaging with these feelings consciously can lead to personal growth and a better understanding of your desires and fears.