Something one male, usually but not necessarily in the 15-45 age group, is wont to say to another male, when they are pleased, or are affirming their choice, feelings, experience, results, or the turn of events in general. 'Fuck' being an emphasiser. Occasionally spoken accidentally to a female, which becomes more comical in effect.

the art of remembering an arousing occurrence or some porn you watched while masturbating, often handy if you have no porn or your in the shower

An affirmative exclamation professed by ecstatic females (or males) during sexual intercourse at the point of orgasm.
It is also a lifestyle brand started in the year 9 a.d.
(see fuckyeahdude.org)