Generally, there are no turns on who should post. It should just be done if someone hasn't done so (meaning I should but I'm in school right now so it's not possible).
I typically like to post less so I can get you guys more characterization; not posting shouldn't be a form of characterization. I also do it less because my posts, if you haven't noticed already, tend to be lengthier for the sake of trying to develop characters at the same time as developing the plot and pushing it forward.
That being said, posting should be done as much as it doesn't involve only two people and leaves others out if they wish to also do the same. It should just be a thing that's done.
Anyway, I'm not in the best of moods. I'll try to have something tonight, but if not, there's tomorrow.