Well, throughout the book, Zamyatin mentions lust though imagery, metaphors, similes and more. One example would be: "Helplessly, like iron and magnet, sweetly yielding to the immutable precise law, I emptied myself into her" (p. 73). You should note that the terminology used by D during this quote is not very characteristic of him as he would not typically say that he emptied himself into her. However, he still uses a scientific side in order to help explain his emotions. You may want to consider making a thesis along the lines of how D's speech changes when he is explaining reality and actual news from when he is describing his own lust.
As for human-like behaviours, I cannot really help you as I don't really understand what exactly you want.