When you get a boner by looking at a woman with some fat on her body, dont go thinking u have a thing for fat women. Because you probably dont. She doesn't have to be fat. That woman you're looking at is thick, meaning she has curves, ass, hips, thighs and all that good stuff.
So it is really important to understand the difference:
Fat: when she has a body with an out-of-control fat mass.
Thick: When she has all the sexy curves that make you go "daaaaamn"
Damn, watch that thick girl doing it with that celeb.