@Melonlity -- Have no fear -- deworming cats and dogs is possible when you use the right technique. Your mileage may vary but I can tell you what works for me.
First of all, I get the liquid dewormer because I've had better luck with that than with pills. Second, I'll get a syringe so I can put the medicine in it and squirt it in the animals mouth. Third, I'll get the help of my wife.
My wife will hold down the animal in question while I pry its mouth open squirt medicine in the back of the mouth. I then hold the mouth shut and stroke the animal's neck and chin until the pet swallows.