Carl Zimmer has been collecting science tattoos for a while now, but recently posted this tattoo of Hayley who has the molecular structure of serotonin tattooed elegantly over her body.
I’m sure there’s some relevant chat-up line for exactly such a situation when you meet someone with serotonin tattooed across their butt, but I’m too tired to try and formulate it, so I shall leave it as an exercise for the reader.
Of course, if you’ve been drinking, refrain from trying to incorporate G coupled receptors into your chat-up line, it’s obviously going to end with someone getting a slap.
Link to serotonin tattoo (thanks Sandra!).
Mind Hacks 
How about “Your place or monoamine?”
I’ll get my coat
Fantastic! Sir, you are a genius!