I work with an eight year old girl who has cerebral palsy. She has difficulty with motor control, and I had not been able to facilitate the production of /g/ or /k/. I had recently seen a post on Perkilou's SLP sharing group on Yahoo about a SLP who used a Dum Dum sucker to push the tongue back so that the tongue tip could not go up. I tried this with the student, and she got a /g/ on the first try. I was thrilled.
During the next session, I decided to show her teacher when we got back to the classroom, but the student threw away the sucker even after I told her not to. We showed the teacher anyway, and she said /g/ without the sucker on the first try. I tried to have her do it again, but after several attempts, she still said /d/. At least now I know that she can. =)