A pocket holster serves several functions - (1) Conceal the outline of the firearm, (2) Keep the firearm properly oriented, muzzle down, and (3) Cover the trigger to help prevent accidental discharge.
I have used three models, a DeSantis Nemesis, Galco leather (horsehide) and custom holster by Ryan Grizzle. All work well as described in the first paragraph.
The Nemesis is a little bulky, with a folded design, and has little or no retention capability. The outer surface is sticky, the inner a nylon tricot. It always stays in the pocket, but the gun can fall out if you slouch or fall.
The Galco well made, but on the large side. It conceals well due to the two piece construction and flat outline, and the leather is soft and supple. The flesh side is turned out, providing ample friction to keep the holster from being drawn out with the gun. There are also "hooks" in the top, front and aft, to catch the lip of the pocket. There is enough retention fpr safety, due to the smooth leather surface inside. If your pockets are large enough, I wouldn't hesitate to recommend this holster.
The Grizzle is very well made, and about as compact as possible. The leather is flesh side out, but fairly firm. It is a loose, blocked fit very little molding or boning. (Boning looks cool, but has no place in a pocket holster.) The small size fits almost any pocket, including dress pants, other than some "euro" styled trousers. When shopping, you should be able to insert your hand to cover a wrist watch and spread your fingers naturally. The most reliable way to draw is to press the top of the gun forward, so that the front of the holster hooks on the lip of the pocket. If it comes out, be prepared to sweep it aside with your weak hand (practice, practice, practice).
When reholstering, the holster should always be withdrawn, gun inserted, and replaced in the pocket together with the gun. That is the only safe way to avoid an accidental discharge, especially with a striker fired pistol.
