A condom: a square packaged device that provides safety during sex
Guy: I want sex but I don't have condoms
Girl: don't worry I got some safety squares
A less popular name for the NFPA 704, or fire diamond
Dude, that substance is stangerous, don’t you see that 3 on the safety square?
The act of discarding the first square of toilet paper while in a bathroom. This removes the outside chance that the last patron touched that piece while removing toilet paper for his own use. This becomes especially important when using a public restroom. Also can be referred to as s-squared.
"Hey man, you better practice safety-squaring when you're done in there."
"Of course I s-squared, what do you think I am?"