Although I've outgrown it, for years I used a belly band holster, but under my armpits. Any loose fitting shirt with blousy short sleeves worked great, even tucked in. You could literally cross your arms across your chest and slide your strong hand through the sleeve of your weak arm and put your hand in a firing grip on the pistol and no one was the wiser. You have to meticulously keep the pistol clean and oiled as it is subject to normal sweat during the day, and wash the holster to keep it from smelling. With long sleeves you would just pop the buttons on the front if in a hurry. The pistol was kept just under the weak arm shoulder. It also had sleeves for 2 extra mags and doubled as a money/wallet carrier.
If your going to Mexican carry at least use the old OSS, trick, get some twine and make a loop, place the loop through your belt, between your belt and pants and you have 2 semi circles. Slide the pistol through both semi circles, and into your pants and that will prevent the pistol from lower itself through your pants. This can and will happen, especially with small frame auto's. If you have a high front sight or a square front sight it may snag. The OSS used this as even being caught with holster in enemy territory was grounds for arrest. If anyone found the string on the ground, well it was just string.