I went to an SLP and we worked on "d" and "t" a lot. I had a lot of tension with the tongue pushing hard against my teeth/mouth. We worked on a lot of light touch / light contact with the tongue, but it was the same positioning. It took some time, but I have a much easier time with those sounds. At this point, you may fear the D sound as well. You can also try stuttering on "D" words on purpose. If you get desensitized, using a technique to help with d words may be more effective.