I'm going to fake a limp at work
How will you go about faking a limp?
I'll put a towel around my ankle, roll off the left shoe and limp around. I want to get out of work.
You should not be faking injuries at work for any reason.  Lying like that is simply wrong.
Who cares?  All I want is my vacation!
If your company has a vacation policy, then the same rules will apply to all employees.  You can earn time off by simply putting in the time at work.  Trying to fake your way into sick leave is not only cheating the company, but your fellow employees as well.