A condom that has been used, and after sex, the bloke leans out of the window, (or aims at a place with people) and chucks it at them. Similar to the normal nerf ball, as in it is weighty at one end, and flys like hell! Appropriate scoring can be made for accuracy and distance of throw.
Bloke 1: "I was making love to my girl, and then when i came, I took it out, leant out the window, and nerf balled the kid in the garden next door!"
Bloke 2: "Awesome! Head Shot?"
Bloke 1: "Of course"
Bloke 2: "Wicked, the full 10 pointer then!"q