If it isn't carbonated, just fill the bottle with a party tap. If it's carbonated, you'll need to chill the keg as close to freezing as you can get it first. Placing a short hose over the end of the tap so you can fill from the bottom of the bottle will reduce foaming.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk