This song is about Elvis Presley. Here's some lyric analysis:
"Jimmy Rogers on the Victrola up high" - Jimmy Rogers, an early Blues singer, influencing Elvis (the baby) at an early age. The Victrola is the record player, played loudly.
"Mama's dancin' with baby on her shoulder" - Gladys Presley dancing with the infant Elvis.
"Black velvet and that little boy's smile" - You can buy a black velvet Elvis painting at any respectable yard sale. Early female fans were drawn to his "Little boy smile."
"Black velvet with that slow southern style" - Elvis delivered some of his songs with slow, undulating hips. Check out "Steamroller Blues" live.
"Up in Memphis the music's like a heatwave" - Sun Studios. The epicenter of early Rock music and where Elvis recorded.
"White lightning, bound to drive you wild" - Rock music and booze.
"Mama's baby's in the heart of every school girl" - A reference to the baby in the early part of the song, being loved by all the young girls.
"Love Me Tender leaves 'em cryin' in the aisle" - Love Me Tender
was a huge hit for Elvis in 1956.
"The way he moved, it was a sin, so sweet and true" - Elvis' legendary hips swivel, the Pelvis.
"Every word of every song that he sang was for you. In a flash he was gone, it happened so soon, what could you do?" - Elvis died suddenly in 1977. (thanks, Ken - Lasalle, Canada)