Sasuke agreed at a young age to allow Orochimaru to take over his body. His only goal at the time was to avenge his clan, and return its honor. Now, because of everything that's happened, it appears he's not going to let it happen. However, Orochimaru has already stated he still wants Sasuke's body, and that he's helping in this war because he doesn't want his experiments to be a waste.
Now the first time Sasuke and Orochimaru clashed, Orochi was pretty much dead. Sasuke beat him due to is really bad conditions.
If Orochimaru goes after Sasuke again, he will be at full power. Sasuke hasn't increased his resistance against Orochimaru's body take over, and Orochi also has the cells of Hashi. Kabuto tried to use a very similar move on Itachi and Saskue so we can assume he was confident in it's power.
Do you think Sasuke gives up his body willingly or does Orochimaru take it after he's weakened?