This is a great idea! This would improve the viewing experience dramatically as it essentially allows automatic skipping towards our favourite parts.
Question - Could you make it so it filters for multiple time tags?
E.g. Allow users to select the time tags to filter for in the settings (e.g. Cowgirl OR Missionary). Then when the button is enabled, the video automatically skips to the first segment matching either "cowgirl" or "missionary". And upon pressing a user defined hotkey (e.g. "A") , this will skip the video to the next "cowgirl" or "missionary" segment.
If you do it this way, this would allow users a seamless way to skip to all their favourite positions with the touch of a button.