Jennifer,
Leave it alone!! As you said yourself, forcing it down causes you to have tension, so that should be enough!! The tongue will raise up during an ee vowel: that's quite natural. It might help you to try and plonk the front of it behine your front lower teeth, but the middle and back is going to arch for sure!
However, if your tongue is slipping back into the pharyngeal area, then this isn't desirable!!
I'd be interested to know which it is?
Best wishes,
Ian Voice wrecker to the stars!
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