Primal Instincts (Blush Series) by Jill Monroe (Harlequin Blaze #378 - Feb 2008)

This was actually two stories in one -- Miriam and Jeremy as well as the main characters Ian and Ava. I actually chuckled out loud quite a few times while reading their stories. Would have loved to read more... didn't want to put it down.

Back Cover: 
Who are they to argue with biology?

Subject A, photojournalist Ian Cole, is sent to ghostwrite a book on sex in various cultures. Instead of finding a white-haired professor, he is greeted by Subject B, anthropologist Ava Simms, wearing only a teeny loincloth and body paint….

Observations…

Sexual energy between subjects increases exponentially. Note the male's quickened breathing and barely restrained urge to do lusty and inappropriate things.

The female, in turn, decides to demonstrate her extensive knowledge of seduction, play and ritual…claiming it's "research." The results? Neither Subject A nor B want the study to end….

SanNGa
..."Speak kind words, and you will hear kind echoes."