I think you're misremembering, though it could be me, it's been a while since I started a new game. I'm pretty sure you pick two things in the beginning. A weakness, which does what he says, makes the area more sensitive and take more pleasure damage, and a secret desire, which is what you are thinking of that makes it harder to suppress the desire.If I remember correctly, the weak spot does what you mentioned, but also reduces less desire when you supress it.
And I wouldn´t exclude the chance of it rising faster too but I am not sure about that
Nothing says you can't pick the same area for both though, making one area more sensitive, and harder to resist desire gain in. Can be a good option, or a very dangerous one.