The are many ways of concealing  a firearm, but when it comes to carrying backup mags, there are far fewer options.   I know plenty of people that carry spare mags around in pockets, but I’ve seen too many times that the top round of  a loaded mag will eventually pop loose or be out of place which could cause a malfunction.   I’d recommend carrying spare ammo along the belt line for 85% of CCW.   There are some tactical jackets that are designed for holding magazines, but I also recommend close the pockets and not leaving them open.   Elastic retention will help hold a mag from side to side movement, but when it comes to up and down movement, those mags will probable hit the ground when you may be reaching for them.

Also keep in mind that there are ways of modifying your mode of carry before you leave the house, some environments are always going to call for different guns and different gear, but it’s best to stick with the best for all occasions.    If you’ve never taken a Defensive training course, I highly recommend going.   You will hopefully get a good instructor and get your money’s worth, but one of the things I can almost guarantee you will learn about, is all of the other students that show up with gear that didn’t cut it.   Blackhawk Holsters are top tier firearm retention  holsters, and they make a single and double stack mag holder that gives you a level of tension without having to deal with a cumbersome flap or snap down mag holder.