Sending an ambiguous message to a female friend was discovered by his girlfriend. How to solve it is the most effective, provided that the female friend and I are fine and like to have fun like this.

Getting used to ambiguity is not a good thing, even a joke can hurt people.

Moreover, if such jokes are played too much, they will easily get angry. Do you believe that your girlfriend has such an affair with other men?

I don't think you have realized your mistake. When you do this, apologize to her and promise! Ask her forgiveness.