Very clever and neat design. The rules explanation is clear and engaging. The task of tattooing two persons instead of just one adds a nice layer of complexity to the storytelling: the player can juggle the unfolding characters by intertwining elements from both.
I find a bit creepy the idea that you cover your parents with tattoes (maybe it's a cultural limit of mine ^__^), so I appreciated the optional rule about different customers.
In these kind of games based on prompts I often find it easier to have something given to me (e.g. "you draw a flaming heart") and then find a way to incorporate it in the story, rather than be given the objective of "you draw something about love". In your deck there are both methods (starting from an image and starting from a concept), which is a nice way of having different challenges for the player.