When a particularly sexually-adventurous chap takes a rusty vice-clamp and secures it rigidly at opposing points of his anus, and proceeds to twist clockwise until the pain is too much to bear and a black hole forms, sucking everything within a 100 mile radius into his super-tight rectum. This will generally produce an especially violent supernova within this man's colon, most likely affecting the next few day's bowel movements.

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