We can also talk about purely H doujins too though we can not post links, I am willing to discuss and recommend some though.
In fact the first H doujin I want to recommend for all Asuka/Shinji fans is Suki, it's very romantic. It takes place a while after EoE and Shinji finally (once again) tells Asuka that he loves her but this time she doesn't reject him, it's totally WAFFy. I feel it to be the best Asuka/Shinji doujin outside of Re-Take ever.
Shinji and Asuka and a Hot Day
Tenohirano Adolescence 2
I also want to recommend two H videos
The first one is ASH, it is very romantic and sweet, I just wish it was translated. I guess it's an AU to either the night that Asuka came to Shinji's room or the night before the Unit 3 activation test.
The other is Aka Yatsu, basically when Asuka's Unit 3 activation test goes south she enters a dream where her and Shinji go at it like bunny rabbits.