A japanese made acronym meaning Time, Place, Occasion. Sometimes used to draw attention to a situation or experiance that was inappropriate or worth noting.
Character A: I love you!
Character B: Awww. I love you!
Character A: But, I love you more!
Character B: No! I love YOU more!
Character C: Uh...guys? Please don't do that during a funeral. Think of the TPO, ok?
Short for sunao cool. It means honest and cool, essentially another moe following along the lines of tsundere. Basically its a character's trait or personality, perhaps the word was created as an opposite of tsundere.