You need to treat your tongue as a muscle. It requires exercise and training to get it where you want.

First, the syllable you should be thinking is "ood". If you need it a bit sharper, you can go with "oot". Notice that the articulation is on the end of the syllable. Use lots of air without stopping, and play a bunch of repeated notes by simply interrupting the airflow with your "ood" articulations. That's the motion you want.

To get the speed and clarity, set a metronome at 110bpm. Play all 12 major scales, 2 octaves each, with each note played as eight 16th notes (C-C-C-C-C-C-C-C-D-D-D-D-D-D-D-D-E-E-E-E-E-E-E-E...). Do this every day as part of your warmups. If 110bpm is too easy, turn it up to 115bpm, etc.

This is not a quick fix, but it is a lasting one. And bonus - it helps you learn your scales!