A comeback. Usually the last resort in an argument, but sometimes the first if you can't be bothered with an argument or conversation. Normally short for "I had your maw" (meaning "I had sexual intercourse with your mother")
'So's yer maw.'
'You owe me.'
'Yeah, well your maw owes me for last night.'
'You're such a gay.'
'I think your maw would disagree.'
'Shit, watch out. Here comes your maw, an' it looks like she's got an erection.'
An unfortunate idea, which for the last 300 years has made it acceptable for many English people to think that Scotland is a region of England. Although Scotland and England have totally different cultures and Scots people are a different race, many people who don't live in Britain believe that Scotland is part of England. It's just like Canada being considered part of the USA, except even more wrong. Oh yeah, there's Wales as well, and they even stole some of Ireland.
"Where do you come from?"
"Oh, in the UK?"
"¿Qual es tu nacionalidad?"
"Si. Mucho, mucho, mucho."