You know the one.
It takes everything for Aziraphale to simply address Crowley as his friend in public so how he found the courage to kiss him in the back room of the book shop is beyond any known knowledge anyone in the universe might have.
But it's so wonderful. And warm. And Aziraphale thinks his lips feel far too soft to be called demonic or sin. If anything, they're Heavenly and the whimper he makes only proves that.