Pep Pep is Tim & Eric's common term for "father" and/or "grandfather." Also, Rim Rim is sometimes used. Most famously Casey Tatum uses the term, often to tell his Pep Pep that he loves him during the Uncle Muscles Hour. In his climactic scene in Steve Mahanahan's van, it is revealed that Casey's Pep Pep is Richard Dunn. The term is also used in Cinco's "My New Pep Pep" - a life-sized mannequin, dressed as a grandfather, which comes with flavored scent pouches, dispenses hard candy, takes naps, and stowes away easily. During host segments, Tim & Eric often say Pep Pep without reason. In the episode Slop, Tim & Eric's replacements say Pepper as an alternative to Pep Pep. During the sketch Night's With Tim Heidecker Eric reveals that his pet Rascal responds to the call Pep Pep. Tim then has trouble pronouncing Pep pep. In the episode Muscles for Bones eric tells the viewers to send in their Pep Pep's bones as well as Mem mems bones. This means "mother".    The term "Pep Pep" is also used as a nickname for Juno A. Cat by KO and BZ.  She responds to "young pep pep". Similarly, a stepfather is referred to as a "step pepper".

The term itself is a common affectionate title for grandfather, used in and around Pennsylvania.

"Pep Pep" is not to be confused with "Pup," which is a term for fecal matter.