I agree with pretty much everything said above. I felt like everyone could see it until I stood in front of a full length mirror in my bathroom and turned this way and that and realized it really was invisible.
Two thumbs up on the tip to keep your hands off it. If you're not fiddling with it, then nobody will notice.
Practical tips: Take care and think ahead:
Don't just plop down in a seat and then hear the thud of your CCW banging the seat back. Do sit smoothly and then lean back so that the grip doesn't hit.
Don't forget to notice if it's windy out and have a gust blow your cover shirt up. Do turn slightly or put your hand in your pocket as you walk to subtly pin your shirt down from flapping. Just look natural.
Bathrooms are probably one of the biggest things to plan for. Don't use the urinals. Go into a stall. Make sure the door is locked. CAREFULLY ensure your weapon is safe from falling out and clattering on the floor!!! I do not using a thumb break holster. I discovered at home that it WILL fall out if you just drop your drawers and sit down. Thankfully I discovered this in the privacy and safety of my own home. (It's also good that it was my Sigma and is completely drop safe). Since then, when I'm out, I always draw my weapon and place it where it will be 100% safe while I complete my business. Almost every stall has some flat on the toilet back, or on the paper holder. Or I use my lap. Be sure to safe it! After you are done, take care re-holstering and don't open the door until you are safe and your clothes are all in position. Take your time and use caution. You will read a story about a cop or citizen accidentally dropping their gun or shooting it by accident in a restroom a few times a year. That's because it is the only time all day that your weapon is dislodged. The other thing, even if your holster is a retention style, you don't want it flopping on the floor with your pants and either making a distinctive sound of metal or (especially) you don't want it visible underneath the stall. Just be careful and think ahead.
Also, watch for kids. Their eye level is pretty low and they can see up at you... That means they might see under your shirt/jacket from below, especially if you are going up stairs.
Good luck!