Get a sweatshirt, and put your non-texting hand on top of the table. Pull that arm slightly into your sleeve so you can't see that hand. Put your other sleeve on top of the table and fluff the end up to make it look like your hand is there. Take your texting hand and push it under your sweatshirt so it look like both of your arms are on the table but you really have one sticking out of the bottom texting.
You could use the jacket thing or what I like to do is when possible put my head down and have the phone under my face. Have the brightness on the lowest and text with one hand and use your other one to block it. It worked for me for several years.