The best way to get into a Uroplatus' mouth is to A) tap it somewhat abruptly on the nose in a downward motion... This may not work with tame CD animals, but will nearly always work with WC... This will stimulate a threat response and cause the gecko to gape... OR B) get a thin guitar pick and slide it into the front of the mouth... The gecko will bite down on it and then release, leaving its mouth open... Most of the time though you'll have to try it a couple times to get the gecko to gape... This method is easy for medicating or assit feeding because if the gecko doesnt gape, you can slightly turn the pick clockwise to "pry" open the mouth and insert the syringe...
Of course do all this very carefully...
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Ben