Redness on a specefic part of the neck of my penis, what can It be?

[fantsu]

If I pass a few days without washing my penis at all, the part that is red soon gains the color of the rest of the neck, less red and kind of pink.This has led to me think if maybe it's the soup or that I'm applying too much pressure, but only this exact spot gets this color. I'm having this issue a long time now, but I have to wash it, so I don't quite know what to do. I'm 18 years old and still a virgin.  It doesn't hurt, but I feel this part more sensitive.

Oh, and I also tried different soups, same result.

I'm going to put links below for a few pictures I took of it;

https://i.imgsafe.org/7cf8cc3965.jpg
https://i.imgsafe.org/7cf8e5609f.jpg
https://i.imgsafe.org/7cf8f61b89.jpg
https://i.imgsafe.org/7cf8f25928.jpg
https://i.imgsafe.org/7cf91b3543.jpg

I hope someone can help me.