look up any word, like ratchet:
 
1.
the act of typing flusteringly while talking to someone who makes you crazy
i was talking with my girl and i was so flustered i was totally fyping
by swords girl November 21, 2010
 
2.
Particularly useful in forums where photos of beautiful girls (or guys, if that's your inclination) are posted for the admiration of others.

It is a combination of "fapping" and "typing".
"She's gorgeous! If I make any speling mistakes, it's coz I'm fyping like a rabbit!"
by Javert October 21, 2011