neck-shaving

[D3Straight]

Hi guys!

I'm new here and would say "hi" to all here. My English isn't bad nor good. So I do my best.
I know, that's not a good start, but it's the only problem that I have with shaving at the moment and I haven't found a solution for it by now.
Here is the fact:

I shave about five months with a DE razor. Everything is fine. Now I started shaving with a straight razor. On the top of the face (cheeks, around the lips,...) I can shave myself easily. But when I shave my neck against the grain there is a problem. When I strech the skin and hold my head a little bit up then appears a deepening between the trachea and the artery of the neck where the blade cannot reach the hair because of the length of the blade (it's a normal 5/8 rozor blade). How I can shave between this deepening? I tried to hold the razor with the right hand and then with the left hand. But no way. With the DE razor is no problem because the blade isn't long. Can you guys help me? I hope so.

Regards
D3Straight