Good advice, except that Uncle Pug neglected to mention that this is only the North American standard. In Japan and most Commonwealth countries, it's typically placed on the other side.Uncle Pug wrote...
1) On your left leg midway between knee and crotch and midway between front of thigh and inside of thigh.
2) Cut or burn a *button hole* in your under garment 3" to the left of midline and even with the crotch.
After all, in those countries, everyone passes on the right.