Concealed carrying fixed blade knives isn't always easy. First off, the companies often skimp on sheath designs. They may be just cheap neck knife sheaths that have no clips or belt knife sheaths with just loops or the materials are weak or any of dozens of issues. Secondly, belt carry can be very difficult especially if you don't have a cover piece. Even IWB with a shirt covering has its own set of disadvantages. It might be hard to get to and also brings the very real danger of cutting yourself. One method of carry I've come to like is pocket carry. It's very concealable and reasonably easy to access but the big downside is that few sheaths are made for this form of carry. I had to good fortune to catch an interesting system for pocket carry while looking at reviews of the Cold Steel Kiridashi in a video by WellAllJuggleKnives.
In the video, the simple neck knife sheath had a single keyring put through one of the holes and then attached to a simple carbiner. The carbiner clips onto the edge of your pocket or in the belt loop. All or most of the knife disappears into your pocket. When drawn the sheath with rise up until reaching the end of its tether. This has an added safety advantage by protecting your thigh from the edge during the draw. Then your knife is out and ready for EDC or crisis use. I carry my Cold Steel mini-tac tanto offhand with the low pocket method while at work and use the belt loop when I have a cover or when out and about.
This is a very simple and useful system that adds a lot of utility to a simple cheap sheath for fixed blades especially neck knives. It can also be used in your car, at your desk, beds, on backpacks, or even hanging on your shower with a high corrosion resistant stainless steel blade. I think the addition of a pocket clip to the grip of the fixed blade could make this system even easier to use. The 2-zero from Nemesis Knives has a clip like this and I would love to try it in combination.