1. Someone who is addicted to sex, meaning they physically and mentally cannot go a certain amount of time without it. Usually results in having sex with someone they normally wouldn't, simply because they need a fix. Similiar to alcohol and drug addiction because in all three, a person is craving a release from stress and/or some form of gratification.

2. A lame reason people give for cheating on their significant other.

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

Holden Caulfield. At least thats what he says.

A sex addict is simply one who is addicted to sex...no further explanation needed...

(See Tiger Woods)

Human male....

someone who cannot live without sex for a long period of time; it's such a deep desire that they would have sex with anyone just to fulfill that constant desire.
also, commonly known among teenagers as "a krystal".
Example; "I was wrong for cheating on you. I was pulling a krystal, and i'm sorry".

-my exgirlfriend krystal is such a sex addict. i swere, she used to try and pressure me into threesomes with her and some random person. it was just plain sick.

-You can't live without sex for a day! your such a damn sex addict! i can't believe you.