Articles about the advantages of AIWB carry for larger guns are available with some searching.
It does not work for everyone, but I can comfortably and completely conceal my FS M&P with a good Kydex holster and nylon tactical belt. I'm average size. The gun is not too big and I have a 5" barrel. It is not too thick, and the grip is not too long (standard mag) when carried AIWB. It will not print with a proper covering garment.
I have carried like this for over two years, 14-16 hours per day. It is doable. Because I carry other gear IWB at the same time, my pants are about an inch larger than my waist. The covering garments are the major component of well concealed carry, but I can wear loose darker t-shirts and polos in the summer just fine.