What would you do in this situation?

Alrighty, SO, to begin, I'm 20, I already have a tattoo (it's Jack Skellington, and it's going up my back and is about 12 Inches long).

My parents paid for it as a Christmas present when I was 18 as this was something I had wanted literally since the day I found out what a tattoo was (there's a ton of meaning, ect, but that's not what this question is about).

I live with them currently as I'm still going to school, and I want to get my second tattoo. I'll be the first to say, it's not a typical "female" tattoo, but I'm not your typical female. I've always been a little off the beaten trail, and my family is well aware of this. I don't want to just go and get it since I do live in their house, and I would never disrespect my parents for this, so does anyone have a suggestion on how to bring it up as a conversation? I want to get The Joker from The Killing Joke with the quote "So why can't you see the funny side? Why aren't you laughing?". For me, the Joker represents being fearless. Not allowing society to tell you how to be or who to be, to be yourself and to live life to its full extent regardless of what everyone else thinks.

My biggest concern is them just saying it will be ugly, so they will say "no", and that's fine, but I would like a fighting chance at this as I've been waiting patiently since I was 12 for this, and I have been saving money from outside my work money that I am putting towards school.

Don't just say "just get it" or "don't get it if you think they won't like it". I just want suggestions on what you might say to your parents if you were 20 and already had a tattoo they paid for.