Run the puffing Billy

When a group of senior men over the age of 70 run a train on your girl. The term is from how one of the oldest steam trains is called The Puffing Billy, and how some of those 80 year old weenies let out a puff of air instead of a cumshot upon finishing

My ex gf said she was going to the retirement home to volunteer, but it turns out she was there to let a bunch of old heads run the puffing Billy on her