It's been a long time. Here's a 40+ second video for your troubles:
Source: Daisy
I started working on this 3 weeks ago and it took forever to rotoscope to track each breast. I did come up with a fancy expression to help with the expanding part, but I still had to go nearly frame by frame for the cutout. The clip is actually quite a bit longer, but her hands come into play and I just really did not want to deal with shadows any more than I had already.
I had to write a new tool for this that I'll probably release by itself as a tiny stand alone script because of how useful it is. I was surprised AE didn't have anything like it. It creates a keyframe on a property that has an expression applied based on the value of the expression.