#32 I would use this.

Yes, this was referenced in the earlier post about good posture. However, it deserves its own post.
Ahem.
How do you remember whether to pull out or push in when you're out of tune?
If I stab you with a knife, what are you going to say?
I know, a little strong for a family-oriented blog, but work with me.
And the answer is not "OW!! YOU'RE KILLING ME!! CALL 911!!"
No.
You will very calmly and quietly say, "It's sharp. Pull it out."
So, if you're sharp, pull it out.
If you're flat...sorry. We don't have a device for that.