First off, welcome to the forum! You made a great choice by joining this forum. I would STRONGLY recommend you go GREEN and join the community; you'll find you make your money back fairly quickly. Also, great choice on the S&W M&P series; lots of guys on here carry them, and we're all quite pleased.
I have a Shield which I use with a Remora friction-fit holster. It is not a tuckable holster. However, Remora does make them, and I am quite close to getting one; I truly love the comfort of my Remora. If you do get a Remora, be advised: get a highly adjustable belt so you can ensure the friction fit is tight enough that you can draw without pulling out the holster, but not so tight that you're cutting off blood supply.
I haven't used one, but I intend on purchasing one in the near future, but I've heard lots and lots of great things about Crossbreed's Super Tuck line of holsters; there are AMPLE testimonials and pics of it online. Google is your friend!
I hope this helps!