What Does Shifting Mean in Irish Dating Slang?

My first day visiting Ireland, learning all about Irish dating and mating, I experienced "The Shift". At first, I was completely clueless and thought people were just asking me to move over. Within about an hour of meeting one particularly kind Irishman however, I learned that shifting is a decidedly Irish slang term. Some people told me they hadn't used it since they were in high school, yet others (mostly men) brought it up in conversation often. In some smaller towns, I was even asked if I "fancied a shift".

So, what does shifting mean, in terms of dating slang? It's referring to making out (for the most part), and usually only in the context of someone you don't know yet and have just met at the bar or club. In some cases, shifting might also mean fooling around sexually, and online I've noticed people refer to a shift as sexual intercourse. During my first month in Ireland however, I only heard the term used to refer to some form of intense kissing.