[mochimochi]

Originally Posted by Casiopea

Try this (on) for size means to consider something, think about something; e.g., an idea, an argument.

To goose someone means to startle someone by poking, prodding, or pinching that person between or on the buttocks
goose - Definitions from Dictionary.com

Can is a slang for toilet; i.e., whenever he went to the toilet.

Oh, we did the same thing as children. It was called "kancho", which means enema in Japanese.