For superglue, I just use the Big Lots Special.
Just Coral sells a good superglue as well (which can be applied underwater). Just make sure that whatever you use is cyanoacrylate.
http://en.wikipedia.org/wiki/Cyanoacrylate I pat dry a rock in the spot I want to glue the coral. For Leathers, less is good with superglue. They are harder to glue due to the slime & expansion, so just place a small dot on the dry spot on the rock. Let the glue set for a few seconds. Remove some of the excess water from the coral in the spot that you're gluing. Set the coral on the glue. With leathers, use as small as a surface area as possible. Otherwise, when the coral expands in the water, it will pull itself free of the glue. Let the coral sit for about 20 seconds outside of the water for the glue to fully set. Place back in the tank and voila! The sooner you can get the coral back in the water, the better. Place in a place of medium to higher flow to remove the mucous...and run some carbon.
I've always used superglue on everything from green star polyps to SPS just due to the ease and inexpense.
I've never lost a coral this way. If anyone has had negative experiences with this, please post, as I don't want to lead anyone astray!