When I'm playing a performance, I often find myself speeding up. Over the course of a tune, I may speed up to the fastest I can play the piece, or even beyond. I find myself unable to slow down smoothly, even though I know I am playing too quickly. If I stop playing, pause a moment, and then start playing again, I can slow down, but I'd rather be able to slow down smoothly such that it's not terribly noticeable, or at least not as noticeable as stopping altogether.
This may have something to do with stage freight, given that the adrenaline dump I get during a performance invariably causes me to play too fast. However, I have difficulty smoothly slowing down even when practicing alone.
I've read How to keep the tempo still stable?, which gives practice techniques for maintaining a steady tempo. My question is what are practice techniques that I can use to learn to smoothly slow the tempo back down after it's gotten away from me.
Context: I play the banjo solo, often singing. I do not play in a group.