The "Other F Word" phrase originated on March the 25th 2014. Ron, Pepper, Shelby and several callers were offering advice for Fez regarding his sexuality. The topic shifted to Fez's hatred of the homosexual slur "Faggot". Pepper and Shelby use this word to provoke Fez into a fight. On this occasion though a gay caller told Fez that his hatred of the word was ridiculous. The caller stated that he frequently greats his friends with the expression "What's up Faggot!" (recorded for the famous drop).
Ron spent the next few minutes trying to force Fez to say faggot. In order to avoid this, Fez opted for the expression "The Other F Word".
The expression is still commonly used by Fez as a way to avoid using the slur. Occasionally it is used by Pepper or Shelby when mocking Fez.