Well, "slideways" is almost impossible to translate because it's a play with words. But yet I could think of better German translations than "Wuuuusch!". "Reingerutscht" might be ok, because you slide ammo into your magazine ("Du rutschst Muni in Dein Magazin rein"). That's also a nice play with different meanings of the word, because while sliding into your opponent you are sliding bullets into your clip.