Just in case you aren't currently advertising what you do on your shirt Nordstrom has come up with a solution to this quite large problem.
Of course you have to be a substitute teacher if it your job you are informing people of.
Or you can buy one in support of substitute teachers everywhere!... not that we (the substitute teachers everywhere) are getting any money from the sales.
Starting to think I should be wearing something like this but maybe instead mine will read
"Yes, I am still a substitute teacher
No, I have not gotten a teaching position"
It will save me from answering a lot of the exact same questions.
Will you be running out to purchase one of these lovely shirts?
I will not be because...
1) It is a little over $30 Canadian (plus shipping and taxes still)
2) I don't want to advertise what I do on my shirt (I also wouldn't get one that said "Teacher")
.... but I can only say for myself.
But if you are interested in the shirt you can find it online here.
Or just go check out the closest Nordstrom to you.