(USA Girl) What is the deal with you Brit Girls and your obsession with nips?

My gf is British and she obsesses over shaking a bottle of milk side to side and then opening it up and spraying it at me (and her friends). When we first started dating she asked me if I had ever sprayed milk out of a freshly opened bottle and I said no, and she said it was a female thing. I asked the girl at the tiki bar if she's ever sprayed milk and she said yes. <br><br>Is this a thing?