Hey, sorry for the late update, I didn't get a chance to post until today.
This week I've mainly been working on making a dynamically drawn throat, so that the bulge is controlled completely in code. I've got it to the point that it matches the current neck, and the basic animation is set up. I need to work out a better way to adjust the actual shape, so that it's faster than editing a bunch of numbers, but I think it's promising. It's definitely much easier than drawing the bulge manually.
The size is still limited by collars, so it can't get too huge, but at least it means the throat bulge can finally adjust along with the penis size slider, and the shape is much more flexible (the screenshot is an exaggerated example). I have some ideas for other improvements now that I have more control too, and I'll probably change the toggle option to a slider so that you can choose how obvious it is.