The term 'Bopper Lead-In' is a reference to the 1950s rock and roll genre known as 'rockabilly'. The term was coined by Bill Haley and His Comets, who were one of the first bands to popularize the genre. The term 'TEENY' is a 5 letter word which is an informal term for a small person or thing. In this context, it could be used to describe the lead-in to a rockabilly song, which is typically a short, fast-paced introduction.