What I think makes her terribly sexy
She is exotic and has a killer body. She also has a fierce attitude and conviction to her motives. She does not have to be pleasant or kind. She seems like she can be a real bitch, but that is also very sexy for her. But there is also a peculiar vulnerable side to her. While she has played femme fatales and surly roles she also has played the damsel in distress in a couple of parts. So she is not your atypical implausible badass that Hollywood creates like Angelina, J-Lo, etc.
We've seen Tia get beat up in "True Lies" and other roles. So while she can be tigress, she can also get hurt. And this is what i find so sumptiously sexy about Tia. I'm sure i'd hate her personality, but still want to do her nonetheless.