I've had to do that a number of times at work, for sick reptiles. Unfortunately, I, and my coworkers, always have that same problem. They rarely get better, too. But maybe my coworkers and I just suck at administering it. So far, I have not found a way to successfully give it to the reptiles/amphibians without having to force their mouth open and eventually creating a sore (except for one leopard gecko who seemed to love it).