Watch the Are You Just Happy to See Me online guitar lesson by Jason Loughlin from 50 Rockabilly Licks You MUST Know

This is from Jimmy Lloyd’s I Got a Rocket in my Pocket. It's a combination of a straight-up shuffle and a walking bass line to introduce each new phrase, closer to how a pianist would play a shuffle on early rock-and-roll recordings, with this kind of walking line. You can hear this more prominently on Bill Kirchen's cover or listen to the Jerry Lee Lewis version and pay attention to his left hand.