When you decide to Pump your pals sister and go back to her flat. Everyone knows your pumping her but rather than tell everyone the truth about where you have been, you just say you stayed at Billy’s House.
“What were you up to last night Birnie?” “Oh you know just staying at Billy’s house”
A saying that emphasizes the s cons part of something. For example if you see a horse of spiders you would say “giant horse” and then when the massivespider appears you finish it off with “cock and balls”