FPS Animation with particles

ive been messing around for a couple days trying to figure out how i can make my character have a particle that looks like pee. sort of like a prinkler from the camera. the game is in first person view, and i want to press a button and have the pee(particle) show on camera as if the character is urinating. the only particles i have is fire and smoke. so if i could get a answer of how to create the stream affect it would be great. thanks. and if you dont know what i mean heres a link of a actual game with it in it. http://www.youtube.com/watch?v=bTq29h9tYZY