Have some humiliation shirts made up.  A fun creative exercise…  A lot of fun at the t-shirt shop seeing the shock as you place your order or pick it up.

Then, where them around the house and nonchalantly want to go out to the store with him, run errands, or go to a friend’s house.

He will likely panic a bit asking if you could or would change.  Just slip a short over the top.

That way, you can tease him more while you are out.  “It’s getting hot in here…  I should take my outer shirt off”  or unbutton your shirt a bit, so some of the phrase is exposed.