With MySQL-Enterprise Montior through firewalls

Sometimes it is nice to show customers the functionality of MySQL-Enterprise Monitor (aka Merlin). I install the agents on the servers and the dashboard runs on my laptop. But very often only ssh is open to these servers.
So how to dig a whole through the firewall for MySQL-Enterprise Monitor?

laptop> ssh -R 18080:localhost:18080 oli@where_the_agent_sits

Maybe trivial for you but for me its hard to remember...