Sorry to be preachy to you here .. but you should never let your dog dictate what you do or how you take walks.  Take them together on a walk. If you have someone who can walk the female ahead of you where he can see her that would be fine. If he tries to pull you proven correction methods to stop him.  When he stops pulling and misbehaving.. you can have the walker with the female stop and reward the male with some closeness.  Keep doing this until learns. You will have to correct unwanted behavior.

Regarding the Presa Canario - The Presa is not like a terrier that likes to chase little furry things. They were bred to grip cattle or other domestic animals and subdue them.  Don't expect your dog to naturally want to do something that is not in its genes. With enough training you can have your Presa chasing things but be careful what you wish for.  At  6 months old you should just enjoy the dog and train her for what you desire. Please see stage 7 in this article about the stages of puppy development.