This is an area of my face where I naturally go ATG. The trick for me is in the stretching. Along my jawline my whiskers grow from chin to ear. As I shave my cheeks WTG I reach over my head with my free hand and pull the skin up from my cheek bone. This pulls the jawline up onto cheek area and it gets shaved XTG. On the next pass I shave from ear to mouth with the same stretching. This is XTG for my cheeks but the jawline that's pulled up on the cheek gets ATG in the same pass. Then as I shave my neck (which grows in several directions) I tilt my head to the side (left for shaving right side, right for shaving left side) and tilt my chin up, stretching the skin on my neck and pulling the jawline down onto the neck. I shave down and back to get as close to WTG as I can, then on the next pass with the same stretching I use a kamisori grip and shave up toward the front. As the blade gets to the jawline skin it cuts ATG and I use a little scything as I finish the stroke. The result is a jawline where I (or more importantly my wife) can run a hand from ear to chin with no sandpaper feeling.
Several vids on stretching/shaving technique talk about this, but it all depends on your growth patterns.
Hope it helps!