For the spare mag to my Glock 19 I use a 1st generation Safariland 71 pouch on my support side slightly behind my hip so it conceals well under an untucked t-shirt.
My uncle uses an old folding knife belt pouch with a snap cover flap. Still has the Buck Knives logo on it. He once told me that was the key to CC, not advertising your armed, and no one thinks twice about a guy with a knife on his belt.
I do the same, for much the same reasons, but mine says "Leatherman." Even in places where a big knife might raise eyebrows, no one looks twice at a guy with a multitool pouch...
In case anyone else is interested, the nylon pouch from a Leatherman Surge fits 7-8 rd. single-stack 9mm magazines pretty nicely. My 6 rd. XDS .45 mags fit as well, but were more snug; the 7-rounders were a bit too tall.
Edit: oops, didn't see essentially the same post on the second page.
