Alternate ways of spelling: Faygasm, Fyegasm.
To have a fangasm over Fai D. Fluorite, from Tsubasa Reservoir Chronicles, a series produced by CLAMP. CLAMP are also the creators of CardCaptor Sakura, Chobits and xxxHolic.
Not uncommon because the character Fai D. Fluorite is so extremely sweet, hot, sexy, angsty, and all around FANTASTIC.
P1: I love Fai.
P1: He made me Faigasm.
Once you have a faigasm, having a fangasm isn't as good.