Disclaimer: Unfortunately for me, Good Omens belongs to Pterry and Gneil.
The first kiss was awkward. It wasn't as if either were inexperienced--even angels get curious now and again, and lust was practically a job requirement for the demon--but it was the first time either had tried to please someone whose habits and desires were as familiar as his own. Noses bumped, teeth clashed, and they turned into a pair of bumbling fourteen-year-olds; but in the end it turned out right. They had, after all, been dancing around each other in a slow courting ritual for the last six thousand years. They had to get it right sometime.
At any rate, once they got it down pat, neither Aziraphale nor Crowley seemed especially keen on giving it up.