A theoretical act of self pleasure, often described as masturbation squared, or F=M^2. Can also describe intense masturbation, or simple everyday masturbation for hyperbolic effect. The word is simply a contraction of the slang term 'fap' and the word 'masturbation'.
"My parents just caught me fapsturbating to skinemax, no tv for a week."
"Man, that's harsh. They always say fapsturbation is a sin, but we know everyone does it."