This phrase literally means "Go and come back", but it's more like a combination of "Have a good day" and "See you later."
Here's a breakdown of when you would use it:
* When someone is leaving the house: This is the most common usage. You'd say "itte rasshai" to someone going to work, school, or running errands.
* When someone is leaving a specific location: You can also use "itte rasshai" when someone is leaving a place like a restaurant, a friend's house, or a store.
Other phrases:
* "お元気で" (ogenki de) - This phrase means "Stay well" and is a more formal way to say goodbye.
* "またね" (mata ne) - This phrase means "See you later" and is a more casual way to say goodbye.
The best choice of phrase depends on the context and your relationship with the person.