It's been less than a week now, but it's looking good.
I was looking online for solutions again and came across someone saying that he assumed a limbo-like position, throwing back his head, and did 10 repetitions of such an exercise twice a day. I didn't think that would work for me, but I was intrigued by the idea of throwing back one's head. It did feel like the tongue settled in its natural place then.
My situation was that I had just learned that something which had been stressing me out was okay, and I was feeling rather sluggish. I suggest trying this on a low-stress day and consider a hot bath or massage to help.
What I did was remain super focused on keeping my tongue from doing it for an entire day, throwing my head back when my tongue tried. My results weren't perfect, but they were very good. My attention was always there, and I never back slid for more than a few seconds.
The amazing thing was that when I woke up the next day, ready to go at it again, it was much, much, much easier. Yes, I kept focus, but far less attention was needed. I also used a toothbrush to clear food debris, not wanting my tongue to make any of those aggressive motions.
I'm about 5 days into it and yes I'm still paying attention to my tongue, but aside from sucking a bit in my mouth, my tongue feels normal as it hasn't in a year or two. The urge isn't even there. It's amazing.