A sleeve tattoo covers most or all of a person's arm. Do you know anyone with a sleeve?
I use to know someone with a sleeve tattoo. It was entirely Pearl Jam-themed. But I haven't talked to him in years. 
Apparently they also use this term to refer to a large leg tattoo - but I've never personally heard it called that.
A leg sleeve? I've never heard of that either. I've got a few tattoos myself. Someday I'd like a half sleeve, but probably not the whole thing. On my arm, of course, not my leg. 
Yep a leg sleeve LOL!  You could get a quarter sleeve that only covers part of the arm 
That's probably what I'd want. Do you have any tattoos? 
I actually don't but it has more to do with the pain of it than anything else.  I mean inserting the ink into the dermis layer of the skin with multiple needles?  
The needles are definitely a valid concern. If I remember correctly, it was a different setup for doing black lines versus shading and color. Do you know anything about the inks composition?
Well, I know that traditionally it meant rubbing pigment into cuts made into the skin - now of course you have ink and a tattoo machine to reduce the risks.
That sounds pretty extreme. Now it's probably a lot safer. Are there licensing restrictions?