Dang, you took the words out of my mouth! I don't mind, though - it's too good a game for that. :P
[SPOILERS AHEAD]
Anyways, here's how to get all three endings:
Ending 1: Be as uncooperative as possible. Defend Iggy, choose the snarky answers which are at Orlam's expense, etc. Seal your fate with an uninterrupted "fuck you" rant to Orlam.
Ending 2: Mix up your responses between submissive and self-deprecating as well as being uncooperative. DO NOT rant at Orlam if given the opportunity.
Ending 3: Be the sub to Orlam's dom. Capitulate to Orlam at every available opportunity, and be sure to snark at your own expense, never Orlam's. (This ending prevents you from ranting at Orlam.)