what rove mcmanus (an overratedtalk show host in australia with lame jokes) says at the end of every show of 'rove live', which by the way has some very cool and funny guests.
A statement used to replace a term such as "Swear to God" to really put the point across that you're telling the God honest truth. If it's obviously a lie and someone claims "mums", their mum is thought to die.
Person 1: Did you transfer me the money?
Person 2: Yeah broof course Person 1: Say mums
Person 2: Mums cuz