A person who regularly conceives 'Plaister's' has a certain characteristic which can formally be known as 'Mr smooth'. The general definition for a 'Plaister' is having sex with your girlfriend on a unit of work and/or any other peculiar place for intercourse. Whoever gets plaistered, becomes a plaistee.
Hey babe, are you up for a Plaister on the fridge tonight? Me and my girlfriend had a jolly good plaister last night! I plaistered her all over the kitchen!