What does it mean when people from Canada and US say chamungus in meetings?

I am from slovenia and this week we have 5 people from US and toronto office visiting us for trainings. On monday when we were first shaking hands and getting to know each other before the meetings they would say something like "chamungus" or "chumungus" or something along those lines. I googled it but I never found out what it means. I just noticed they only say that word the first time they are meeting someone.

Anyone know what it means or what it is for?