It means exactly what the word says, you go back to the Xbox dashboard. Doing this cuts the connection with the server and erases the current game data. You still take a loss but whatever other stats you had in that one match you lose. Pretty much kids or childish adults to it because they can't handle someone killing them one time in a match. you can tell if a host dashboards because the infamous "connection interrupted" will pop up on the screen and you'll either jump or stutter across the map until it resets. Host migration happens when the host just regularly quits a match.
Everyone on GameFaqs pretty much is a troll. This site honestly has the WORST user base I have ever seen. -Tuggboat1121