I've recently learned that for the ch and j sound, our tongue must be touching the alveolar ridge. I never knew about it until it was mentioned to me. I was asked if its the same position as the t/d because most diagrams seem to depict it with the same position as t/d. Correct me if I'm wrong but, I feel like the ch and j sound is further back in position compared to the t/d position. For t and d, I would use the flat of my tongue tip. When I make the ch and j sound, it doesn't feel like I'm using my tongue tip, but rather my blade; it feels like my tongue tip is hanging off or down. In addition, the area of contact seems to be further back on the ridge while for the t/d, it's near the teeth. Do you guys agree or is it just me?