Anthony,

How's it going. When I dose my new geckos with panacur (or any other oral med), I usually dab the appropriate dose from the syringe onto the end of the nose and let them simply lick it off. Usually I don't even handle the lizards when I do this. Sometimes this goes a little faster if you give them a spray to get them licking their faces first. I almost never have any trouble doing this. If you want to open the mouth though you might try something thin like the edge of a baseball card or something. Good luck with your new lizards.

Doug