Minor flirting or copping a feel you may have, but like most long time fans I'd be surprised if D went from sex fantasy Martin dream to full on sex.
D will first have to have the inevitable internal struggle over what she wants and if she should go for it. Then she will have to breach the subject with F, then a long discussion, then F getting turned by the idea of D getting blacked (possibly with F wanting to watch D) but he fears pushing her too far too fast so he "relents" and give the okay to pursue Martin, then D gives Martin fuck me signals, then soft sex, then when D has an excuse for her sexual actions we get full on D+Martin sex, and then it's New Years again.