Gascibating is a bastardisation of the word "fascinating". It may be used in two ways.
1) As a sarcastic response of false interest.
2) As an enthusiastic and silly response/descriptive word similar to "fascinating".
Jon Martens: I just ate some cheese.
Keiper: How gascibating.
Kyujuni: In Canada milk comes packaged in plastic bags.
Moinex: That's gascibating ! Although not as gascibating as Allenby's giant inflatable hands !
A purveyor of crap. One who seeks to persuade another that his or her self-serving ideas should be adopted, despite their crappiness.
"Moritz, you craphound! Leave me alone!" -- Burt Lancaster, "Local Hero", 1983