WARNING: Be prepared for some cheesy and awkward english!
Well, for me it needs more than just some nice body parts like tits and ass to make a girl sexy and interesting. She needs to have a nice face and a big portion of charisma and aura and, of course nice body parts. All this little and BIG details need to work right together like a clockwork and are so important.
There are lots of models and porn stars with big tits out there but 99% of them are like dull items. They are not able to light any fire.
Christina, for whatever reason is different. It works well for me. Somehow im glad that she did not start with hardcore when she turned 18. I would be probably impotent today from permanently jacking off.
This Buffy girl, for example has nice boobs indeed but kind of an empty and suffering face and shes pale like a naked mole. On a white sofa in an bright room, you need to call her and following the acoustic to find her. Beside her curdy boobs there is nothing really interesting. Her complete lower body doesnt look sexy at all. Her body language feels uninvolved to me, kinda automated, hard to describe. Just my strictly subjective impression of course and not meant to be a grinch.
Yep, Christina was a rare gift to men and shes still unrivaled to date.
Have a nice weekend Folks!