Pick up your cat nonchalantly, as if to simply carry him to his supper dish. They have little or no interest in fashion as a rule. Once you are inside the bathroom, speed is essential to survival. In a single liquid motion, shut the bathroom door, step into the tub enclosure, slide the glass door shut, dip the cat into the water and squirt him with shampoo. You have begun one of the wildest 45 seconds of your life.
Cats have no handles.
Add the fact that he now has soapy fur, and the problem is radically compounded. Do not expect to hold onto him for more than two or three seconds at a time. When you have him, however, you must remember to give him another squirt of shampoo and rub like crazy. He'll then spring free and fall back into the water, thereby rinsing himself off. Next, the cat must be dried.