I'm not sure if this has been mentioned, but there is the email in the WikiLaks Podesta emails asking about playing dominoes on cheese or pasta. (http://archive.is/JBft7))

I was searching for what the term could mean, and came across this urban dictionary definition from 2011 (http://www.urbandictionary.com/define.php?term=Dominoing)) (https://archive.is/NhzTM)::)

the act of public sex on car parks, namely beside pizza takeaways, where said act could be construed as statutory

That matches up with what I came across in a book called "The Mysterious Plus" by William Tarvin, a book I have never read personally (https://books.google.com/books?id=CtaPBQAAQBAJ&pg=RA3-PA304&lpg=RA3-PA304&dq=domino+sex+act&source=bl&ots=F1fYM1jeUa&sig=P1PYOrtfHVQgUZsM7a0KIckiyz4&hl=en&sa=X&ved=0ahUKEwi68fLu7_vQAhUH7IMKHQZUCwwQ6AEIRDAI#v=onepage&q=domino%20sex%20act&f=false)) (https://archive.is/h8dmB))

He has a website here: http://tarvinlit.com/wordpress/ (https://archive.is/7YyQV))

I must stress that I know almost nothing about this guy or this book as I literally just found it.