Easier way to define a deform field...

Please, PLEASE tell me that there's a more direct way to define a deform field than manipuating the sphere! 

I'm working on a figure at present and, quite frankly, all of the deformers wreck the inner shape of her butt. As soon as I change a pose, her tush gets all flat in areas it shouldn't be flat! Now, I know how to fix this (and have had some success with using the DForm tools) but defining the area with the sphere is clumsy and imprecise (I wind up grabbing bits of the opposing cheek, her crotch, etc.) 

I played around with the "Node Weight Map Brush" and it DOES allow me to directly select the polygons I want to edit. Yay! However, there's nothing I can do with that ease of functionality when it comes to defining those polys for a DForm. It's right there! All highlighted in yellow, EXACTLY what I need! Would a simple button to define a selection be that difficult to program? OR include that "brushing on the surface" selection capability to the DForm tab. Seriously - I'm new to this - but this ONE tiny piece of coding would elimate my need for Zbrush (at least, until I figure out how to make clothing.)

Then again, I can kinda understand why they don't include it...