BB and LL aren't jerks--just having some fun at Femme's expense. They're a lot like Clark's buddies; quick to poke fun, but sure to have your back when the chips are down. You'll see a bit beneath their playfulness in Strip 43 (which'll end this scene).
When someone laughs so that their drink comes out of their nose, it's a spontaneous reaction rather than an elaborate one - therefore I read it as at least LL being an actual jerk. Unless this was somehow a VERY unexpected or funny thing for Femme to say... but if that's the case I really don't see it. Maybe I'd get it if I knew the characters as well as they know each other, but I don't :/
Reading the page again I guess LL's drink-through-the-nose laugh is not in reaction to Femme's statement, but rather in reaction to BB's joke. I misread it the first time by a) that's a long time to be drinking continuosly and b) I didn't find the joke funny enough for such a laugh. But okay, I get it, LL is not a real jerk here.
Yeah. I think LL's reaction was kind of shocked embarrassment (kind of making her hold her breath for a minute) followed by the snort from BB's comment relieving the tension.
None of the heroes are saints by any stretch, and they just goof around when hanging out away from public view. It's also safe to assume that none of them has exactly looked for a long-term relationship. They're still relatively young (mid to late 20s) and not exactly in a relationship-friendly profession.