I didn't focus on OP because he already knows what he wants. Most people need help emphasizing with the other person not with their own wants/desires and compromise requires empathy. There are situations where someone is being over-accommodating and getting walked over but I didn't get that from the tone of the question.

Asking forgiveness later is another advanced level topic but it generally goes hand in hand with a good working relationship that has already been established. Without that its a quick way to get reprimanded or fired.

Remember, at the end of the day you are spending time on this specifically to get what you want. Its not an altruistic act for your manager.