I can carry my Kahr CW9 in a holster under a polo shirt. During the winter, I wear a coat with a larger gun under it.
Being from Texas its near impossible to conceal carry your weapon. Its just too damn hot to wear thick or oversize shirts.
I was talking to a crane operator while at a job and we were bs'ing when he brought up the concealed weapon topic. He said if you see a middle aged white dude with baggy shirt its best not to mess with them because you probably will get shot dead. LOL he is right.