(yah-ō'-ē fahn-gûrl vī-rəs)
NOUN: A highly infectious, medically undetectable virus quickly becoming a pandemic amongst female anime fans. When fully fledged, the virus causes the infected to have an unhealthy, annoying infatuation with yaoi slash pairings. Common symptoms are interest in yaoi fanart, urges to write fanfics, wearing of cat ears, and glomping tendencies. It is spread either verbally or by means of the internet. It has even been known to cause death by compelling the infected to either glomp someone until their bones crack or annoy somebody to the point of suicidal intents. It is extremely important to defend yourself and your friends from the infection and influences of the virus by avoiding diseased persons at all costs and possibly wearing earplugs/masks should you ever be in the presence of a yaoi fangirl. Mental status may be altered, however, and psychological help should be sought out after contact. Those of us who are already anime fangirls are prone to catching the disease. There is no known cure.

Noun: a friend who is usually only called upon by a friend when a more primary/prominent friend is unavailable.

Taken from the term “second string” in an athletic competition situation. In football, if the star quarterback gets injured during a play, the second string is called off the bench to replace him/her. A “Second String Friend” is essentially benched until needed, if ever.

Synonyms: Plan B, Second Choice, Secondary Friend, Benched Until Needed