One of my favorite Chinese expressions is mashang, which literally means "on the horse." It's functional meaning is to indicate that something is about to happen — it is imminent. I used it earlier this evening at the gym. I got there ahead of my friend and was already doing time on the treadmill when Mr. S, one of the personal trainers came by and asked me where my friend was. Mashang guolai, I replied. She's on the horse. She'll be here any minute.
As a slightly impatient foreigner (aren't we all?) I often get it thrown at me when I ask when something is likely to happen. "Mashang." Which is another way of telling me "I know you want to hear that it will happen soon, so that's what I'm telling you, but in fact it will happen when it will happen. Be patient."
So the next time you are running late and your friend calls to ask where you are, just tell them you're on the horse. And now, it's late in the Middle Kingdom, so it's time for me to get on my horse and head to bed!