Parent (or Parents) that enforce a financial, time and effort burden on their friends as they cannot be bothered to organise baby sitters to go to bars / restaraunts and instead always host an inferior event.
These parents always find excuses not to partake in activities, holidays, evenings etc and become overbearingly dull.
Brian: Hey Steve, are you coming on Johnny's stag do in Eastern Europe, we're going to shoot some tramps with some armed prostitutes??
Steve: Sorry Brian, Sarah's organised some 'drinks and nibbles' with the NCT lot. So I need to wear that new polo shirt that she bought me and keep everyone topped up with Waitrose quiche and hummus
Brian: Oh yeah. Johnny said that you'd become a Cunt Parent