I've always done the whole quart at a time, for the past several years (every day for the first year). I lie on my left side and take up to 15 minutes to get the coffee in there using an enema bucket and coffee grown just for that from sawilsons.com. I put the tube a foot up in there, a few inches at a time letting some coffee out as I go to loosen up the muscles and to keep the tube warm and flexible.
Then I lie there for another 20 minutes. Usually after 10-15 minutes I hear/feel a squirt of bile from my liver. I have candles burning and use the time to run healing energy - my special time of the day just for healing, first thing in the morning.
The coffee stays in the sigmoid colon, where there's a closed circulatory system from there to your liver through the hemorrhoidal vein. The coffee doesn't make you wired because it never gets to your gut.