I’m not an artist, so I’ve never been asked this question. But it still bothers me to no end, because why not ask your tattoo ARTIST to draw your idea for a tattoo. They’re artists, not just “tattoo-ers”. And they know better than your artist friend what will translate from paper to skin. Not every design will work on skin, and a tattoo artist can tell the difference, whereas the random friend you’re asking probably won’t.
Also, tattoo artists aren’t Xerox machines. There are limits as to what you can do with a needle, and they are the most knowledgeable as to what those limitations are. It’s fine to get a friend to make a very rough sketch of what you want, but you need to know that it will have to be tweaked in order to look the best it can. Trust your tattoo artist.*
*Note: This does not apply to your buddy that’s willing to tattoo you in his basement for 20 bucks. Never go to a scratcher, please.