I think it might be like a cross-stitch, corset string type thing, judging from his other fashions (sorry, I don't know fashion terms either XD) although there is a pretty good chance it might be bare because of the way the sides of the dress looks on the mannequin.
Wow, great ^_^ It really does look like a drop of life. The only thing that kinda threw me off was the rumple of cloth in the front, that hangs over the belt (which I really like. The belt's very pretty and sparkly). It looks somewhat like a random fold of cloth. Other than that, though, it looks absolutely beautiful Great job.
What makes this really cool (whether you intended it or not) is that the front 'poof' in the fabric makes it look like this dress could fit a pregnant woman... Thus the theme of Life fits even better! This is gorgeous.