Quick Definition: A reference to the Fast Seduction website, the home of mASF. It’s no longer active online as of 2019.
The fucking manual usually refers to the FAQ and Player Guide section of the Fast Seduction site, which serves as introductory reading for new PUAs. The term can also reference foundational material in the community, such as The Game and the Mystery Method Venusian Arts Handbook.
Source: Fast Seduction