It may feel purely carnal, but in fact it's about the urge to mate and pass on your DNA via offspring. Without lust, it's fair to say our species would not survive.
" The accuser is a knight of your own household. Ser Osney Kettleblack has confessed his carnal knowledge of the queen to the High Septon himself, before the altar of the Father" .
I wish now to review in memory my past wickedness and the carnal corruptions of my soul--not because I still love them, but that I may love thee, O my God.
And book two of " The Confessions" has a great beginning: " I propose now to set down my past wickednessand a carnal corruption of my soul." So you expect sex.