Are there any suggestions from you guys of what fx to throw on bk vox that are sexy and R&B like, other than pan and eq and AT?

I'm close using waves renaissance, but I feel as if there is one elemt I'm missing that the pro's know about on backing vocals that I hear on the radio?

P.S. what does the Eventide stuff do cause I hear that it's always present on vocals....can this be done with waves?

Thanks a million