The only coral that I target feed is my sun coral, which only opens at night. I tried to do it with a surrenge without much luck. I was also feeding cyclopeeze, which was working but eh...
About a month ago I got a turkey baster from the 1$ store and a 59 cent 2 liter, cut the bottom off and cleaned it out. What I do, not that its the "right" or perfect way, is this.
I put the bottle over the coral vertically, just like you're going to set it on a table except the bottom is cut out to accept the coral. Use the baster and squirt the food, in this case brine or mysis (frozen), into the origional opening. When you do this it cuts the flow so the food isn't floating out of reach and yet keeps it moving inside the bottle.
I've heard of people feeding mushrooms and ricordia frozen daphnia and I've heard of people target feeding xenia with plankton. I say just drop some Phytoplankton in there once or twice a week and call it good.