ummmm...wheat.
Sorry, I couldn't help myself. Get yourself some malted wheat, red or white (I like red better, it has a more wheaty flavor) and a half pound of rice hulls if you are AG. If doing an extract or PM, they make wheat extract and you could steep some darker roasted wheat if you'd like a darker beer.
I sprinkle a little in the bottom of the mash tun, then mix the rest with the ground grist prior to mashing. a pound should be enough for 100% wheat depending on your mash tun configuration.
I usually just throw in a couple of handfuls in the mash. However, you'll probably need a TON for a 100% wheat beer. I would save yourself some grief and do a BIAB instead of using your mash tun.
Wheat gets really globby in the mash. Rice hulls help reduce the chance for a stuck sparge. Usually a wheat beer has a 50/50 or 60/40 wheat to barley ratio and even then rice hulls are a very good idea. I'd really do a brew in a bag or at least line your mash tun with a paint strainer bag.
I'm not sure a strainer bag would help, it's like trying to drain water from cooked oatmeal, have you ever eaten oatmeal? It's kindof like glue, also depends on your grind, water ratio and tun configuration. I'd still add some hulls of some sort to a BIAB 100% wheat.