Chocho refers to the act of dating, or the person you are interested in that you are currently dating. Chochos usually get upgraded to Girlfriend 1.0, unless the guy finds out she's psycho/unfit for a normal, humane relationship. Chocho is strictly a term used for the female human species.
Chocho is an affectionate term that represents some kindled interest in the woman a man is dating. A man does not refer to his Chocho as his Chocho in front of her too early on in the dating game. A Chocho can only be referred to as Chocho in her presence when he is sure she will be upgraded to GF 1.0. Telling a woman she's your Chocho on the first date just makes you sound like you want some sexytime, and that is not going to happen.
Girl: What's a chocho?
Guy: I'll tell you next week.
Guy: Baby, you're my chocho. I want to upgrade you to GF 1.0.
Friend: Dude, I don't mean to crash in on your chocho (i.e. date) with her, but could you lend me some cash?