think 'slashed tires' - hence the origin of the word. slashed is the opposite of wheelz; it means having no wheelz or being overall awkward with girls (or guys!)
The word was discovered by the American alcohol specialist Evan Nelson, who, upon consumption of massive amounts of hard liquor, accidentally combined the words sloshed and smashed to describe himself.
Usually slashed would be used to describe someone who can no long make intelligent verbal comments.