dear God I've heard it all now.
so the op's partner forced himself into her mouth, she ended up in tears and people have no sympathy for her because she used a word which although ill-advised, she has now apologised for using? 
What if she'd been raped? would you have "no sympathy" for her either because of the use of that one word?
I think the term supportive has totally gone out the window here and a part of this thread has been populated by idiots.
Op - ultimately it's simple. If you don't want to do it, then don't. If your dp has respect for you then there is no question of forcing the issue. Any man who respects his partner would never force her to do something she didn't want. I have been with my dh for nearly sixteen years and I can say with absolute certainty that he would never force me to do anything I didn't want, and that is how it should be.
You don't need techniques on how to give a better blowjob, (assuming that you don't actually like giving blowjobs), what you need is advice on how to tackle the issue of your dp's expectation and his forcing you to comply with demands that you feel uncomfortable doing.
If he is otherwise a loving partner and you have a good relationship, then talk to him, outside the bedroom, where you are not putting any pressure on each other to do/not do certain things. Explain to him how you feel and what you do and don't feel uncomfortable with.
But before you do that do ask yourself whether he is like this in other ways. Does he love you? respect you? if you say no to other types of sexual action does he accept that? What about outside the bedroom - what is your relationship like? Blowjobs are a very small part of any relationship, but often the way people are during sex can be very indicative of the rest of the relationship.