How to get a lazy Quarter Horse to lope?

I’m going to be in a schooling horse show next month. I’m choosing to a quarter horse to ride it the western show. He is can be lazy and hard to lope. I do not want to depend on a crop a lot, I’m trying to use my more leg. Any advice for me?
Thanks I need to practice before the show.
Are stable owner does not allow us to use spers.

When you are asking, really push him with your outside leg. Kick or sqeeze!!! That will also help him get the correct lead. Also suggest with you body position that you are about to ask for the canter, and he should pick up. Its okay to carry a crop with you, but as you said, you shouldnt depend on it. Go ahead, give him a little tap with your crop while you are asking and I doubt he wont give it to you.