To watch YouTube 360-degree videos without a Cardboard or VR headset, you can follow these steps:

1. Open the YouTube app or visit the YouTube website on your device.
2. Search for the 360-degree video you want to watch. You can identify these videos by looking for the “360” icon or the mention of 360-degree in the title or description.
3. Once you’ve found the video, play it like any other video by clicking on it.
4. On the YouTube video player, you should see a navigation tool in the top left corner of the screen. This tool allows you to explore the video in 360 degrees.
5. Use your mouse or trackpad to click and drag the video in any direction to change the viewing angle. If you’re using a touchscreen device, you can swipe your finger to move around the video.
6. Additionally, you can use the arrow keys on your keyboard to navigate the video or use the gyroscope on your mobile device by moving it physically to change the viewing angle.
7. Some 360-degree videos may have interactive elements. You can click on these elements within the video to access additional content or navigate to different parts of the video.

By following these steps, you can enjoy the immersive experience of 360-degree videos without needing a Cardboard or VR headset.

See an example below: