Regarding how sweaty Jax is, I have to second drug use. Be it steroids or uppers. From past experience, I am very familiar with that slick, oily sheen his skin always is coated in. Makes me happy I've moved on from that part of my life!
As far as Lala, (ugh, that name!) My take on her is that she wants to be with whoever can get her drugs. Didn't she go home with Jax after the Gay Pride party and they almost had sex, but couldn't? Perhaps someone was struck by coke dick. James strikes me as a friend of uppers as well. They go out drinking together and apparently just make out. Maybe he gets struck with the same problem? I could be way off on that though! Lala definitely likes the feeling of being fought over.