I've been doing the mouse thing for about 5 years now.
He's kinda like a li'l buddy that follows wherever I go.I got the idea from a gal who did a cat face with ascii characters. I figured if she could do a cat, I could do a mouse. Worked on it a long time, till I got one I liked.
It's just the letter "O" both uppercase (ears) and lowercase (nose), periods (eyes) and equal signs (whiskers).
When I do it by hand, I add a body and tail (looks like the number "2" with a long tail), and little toenails.
As for expletives, I try to make up my own. "Mother of Pearl" is one I use a lot. Anything that starts with an "f" and has a "k" in it is satisfying in the mouth -- "frankencense" or "fracture" or "farking gardwobble".
Anybody can use George Carlin's 7 words. I try to be more imaginative.