SUPER GLUE GEL!

[IslandReefer]

Rule one......crazy glues fingers 500% better than anything else!
Seriously folks....I have 2 things that may help you.
First cryoacrylic sets best in thin films....so get it down the crack1
And have a dish of tank water to dip the newly glued frag in....glue sets almost instantly upon dipping...hope your fingers aren't glued.
You can also chip and/or grind, shape "sockets" for the frag, to make it more stable.
If you need more support than that, I would switch to epoxy or epoxy + crazy and bulid a coller.
Hope this helps...FWIW I use cryoacrylic gel for all but my biggest coral frags and those to slimy to glue with anything, like some shrooms and caps