I am pretty new to straights, so please take my advice with a grain of salt. That being stated, I have a full beard and shave my neck only on a daily basis. All of the hair on my neck grows from my ears towards my adams apple. So the normal WTG or ATG strokes up and down are both XTG for me. When I first started I used to pull the skin down to tighten the skin on my neck. That got it close, but I knew I could do better. I read somewhere (sorry, I'm sure it was somewhere here, but I can't remember where exactly) that pulling the skin in the opposite way that the hair grows and shave up the neck. So in my case I pull the skin from under my ears backwards towards the back of my neck. Doing an upstroke while stretching the skin this way (and a good angle and sharp blade of course) gives me a nice close shave.
Pulling the skin in the opposite direction of hair growth helps lift the hairs which will help getting a closer shave without contorting your neck or playing with blade angles that scare me.