A good rule of thumb: if you cannot shove the holstered gun down your pants then you will have difficulties pulling the gun back up during the draw.

An issue is wearing your pants or belt too tightly and not giving your firearm the space it needs to slide out. Most firearms range from 0.75" - 1.25" in width so that is about the size of the gap you will need between your pants/belt and waist to retrieve your firearm. While this is how most commonly wear their pants, we understand not all of us have the round backside we'd prefer and our pants may simply be overcome by gravity without a snug belt. The best thing to do if you wear a snug belt is the little trick in the Overview Video.  

That's where your drawing hand will nudge at the belt, or better yet on the holster directly under or next to the flap to open some space for the gun. It only takes about 1 second to do the move and draw the firearm. That nudge usually makes all the difference in the world if it’s getting stuck. Certainly don’t just keep pulling without nudging, it should come out smoothly and gently. For example with the nudge, if you're right-handed, with your left hand lift the magnetic flap. Then your right-hand nudges the top portion of the holster on the belt out so it opens up the holster. Then with your left hand pull up on the magnetic flap pulling up the firearm with it as your right-hand sweeps and grabs the gun. After about 10-20 minutes of practice, it's a very fluid 1, 2, 3 motion. It is also important to make sure you are standing up straight, even leaning back ever so slightly, pulling the holster up against your body and not out and away from your body.   If your pants or belt are worn really tight, any kind of IWB may not be the best option and you'll possibly have to either wear looser pants or go with an external holster. As much as we want it to work for everyone we know that won't be the case.