Downloading private Facebook videos directly onto your phone without using any apps is generally restricted due to Facebook's privacy settings and security measures. Facebook prioritizes user privacy, making it difficult to bypass these protections. While some websites may claim to offer this service, they often involve security risks or may not work as advertised. It's crucial to respect the privacy of the video uploader and adhere to Facebook's terms of service. Be cautious of any methods that promise to circumvent these protections, as they could compromise your device's security.