I have a friend who has several tattoos. She calls them sleeves. 
There is actually a difference between a sleeve and an arm covered in tattoos.
Really? What is the difference?
A sleeve tattoo has a unified theme where as someone with a bunch of different arm tattoos doesn't quailify techincally.
Who decides what is and isn't a sleeve though?
If they are different styles and themes from each other it isnt a sleeve. A sleeve goes together not a bunch of random things.
What else do you know about sleeve tattoos?
Well as expected it gets its name from its likening to a long sleeve shirt.
That makes a lot of sense. I bet it is really expensive to get those kinds of tattoos...
Well there are half-sleeves and quarter-sleeves for those who dont have as much money or dont want as much of a committment.