On Saturday, Hasard posted that the scene might be from Fantasy Lover by Sherrilyn Kenyon.
And IT IS! From page 210 of Fantasy Lover
He tilted the oyster to slide into her mouth. As the oyster slid down her throat, he ran his tongue up her neck in the opposite direction.Yay I can finally stop frantically trying to match that scene to the book it comes from.
A big thanks to Hasard. :)