Sing that 

When your mate says something ill (strange, funny or medically related comment) and you think that it would be a good idea for them to sing that word or phrase really loudly, you shout, SING THAT!! (it has to be said in an ill high pitched voice too). If your mate fails to sing the word or phrase, a common follow up is, SING IT!

Andrew - 'granulomatous inflammation'. Pete - 'SING THAT!' Andrew - 'GRANULOOOMATOUS INFLLLAAMAAATION!' Pete - 'you're ill.'

Sing that by the ill man December 30, 2011

that's how we sing 

comparable to "that's how we roll," a statement which solidifies a previous action of a group.

Mark - "That party was bumpin'"
Lenny -"Yeah, cause that's how we sing"

that's how we sing by Len September 15, 2004