(This turned out to be a lengthy answer but, a few minor deviations aside, it is on topic.)
There is an ambiguity in OP's post that jumped out at me (all highlights mine):
she gets mad when I ask her if she can perform orally on me. She
literally says "don't ask it!" and then proceeds to do it anyway. And
similarly when I'm going down on her, I like to check whether things
are going ok and that she's enjoying it, so I ask her "how does that
feel?", to which she again replies "don't ask!"
It is clear from OP's interpretation that he feels his questions are the source of his girlfriend's frustration. Going by the words he wrote in his post (e.g. "She
literally says "don't ask it!" and then proceeds to do it anyway) it is also possible that there is something else going on. Without his girlfriend here to clear that up it is impossible to say with any certainty what that might be. But it is not a stretch to infer that this couple's awkward communication style makes their sex sessions pretty awkward also. Which brings me to my next point.
Information sheets and pamphlets published by the public health authority and sexual assault prevention groups in my area routinely state that explicitly asking for, and obtaining, unambiguous consent are a must before engaging in sex. Consent can be withdrawn at any time, they warn, and it is important to communicate with your partner before engaging in oral or anal sex or any other act that may require additional consent.
It seems OP is doing exactly that...and yet. A problem with the explicit approach to consent is that Anglo-American cultural is not sex-positive (to say the least) and talking directly about sex still makes people uncomfortable. Imagine a guy asking a potential female partner..."So hey, do you want to have sex with me?" Yeah, no. It's more like "Do you want to come to my place and watch some Netflix and chill?"
Also, explicit asking is just not very erotic or romantic. And although it is almost a thought crime to say so in 2018 girls (i.e. young women) tend to like their male sex partners to be dominant and in control in the bedroom. (Why this is the case is an open debate...but it is the case and pretending otherwise won't change that. Don't shoot the messenger please.)
So what can we do to improve communication between the genders?
A few things: a) Teach men from a young age to be more in tune with people's emotions, body language and non-verbal communication cues, b) teach women from a young age to be more assertive and feel comfortable expressing their needs and desires...and c) teach and discuss honestly and from multiple perspectives the role of power in sexual desire and gender roles/expectations and how these manifest themselves in the context of human sexuality and western society.
Sadly, this is not going to happen any time soon as a cursory glance at the quality of public discourse around these issues shows. Dark times ahead indeed, but I digress.
The good news, OP, is you as an individual are free to learn whatever you want whenever you want, time permitting. If you want to better understand what women are communicating to you I suggest learning how to read non-verbal cues and body language...it takes time and practice but it can be done. There are lots of books, podcasts and websites that can help you get started. I would also think about how you and your girlfriend communicate...not just during, or about, sex but generally. Is it easy for you to understand each others needs or are there frequent misunderstandings? Talk to your GF about this (but not necessarily during sex!) and always try to communicate your points clearly and unambiguously. Let your GF know when you are unsure what she is trying to convey.
Given that males and females in our society have somewhat different base communication styles, direct and intuitive respectively, some compromise is necessary. If you learn to become more intuitive by practicing the skills mentioned above, and she becomes more comfortable asking directly for what she needs you'll balance each other out and live happily ever after. Well, maybe not but you will be a happier couple and happier couples have better sex. And I almost forgot...listening. If you learn how to listen not just to what a person says but how they say it, you can pick up a lot of information about their mood, state of mind and the subtext beneath their words.
One does not have to spend much time in our society before realizing that a significant number of women (particularly young women, particularly when men are involved) do not feel comfortable asserting themselves. In dangerous or traumatizing situations "freezing" is a common reaction. The socialization process and fear of violence at the hands of an abusive male are the commonly accepted reasons for this. The former is slowly changing but there is nonetheless still enormous pressure on women to be quiet and demure.
Many men still have a "I'm a dude, I can't read body language or indirect hints" attitude. Women have an edge here but, using myself as an example, reading non-verbal cues and practicing active listening came naturally to me (perhaps because I grew up with sisters). Admittedly I am a rarity among men, at least in my circles, but I've known a few guys who took the initiative and learned these skills for themselves.
It is obvious to non-partisan observers (both women and men) that the current discourse on gender roles and expectations has become bogged down and...a bit unruly. Those eagerly awaiting the ushering in of a new era of enlightened man, woman and Jedi are going to be waiting for a while yet. But nothing is stopping us as individuals from observing how our opposites communicate and learning some of those skills for ourselves. This helps us be more effective and empathic communicators (and better partners and lovers) and as a side benefit loosens the gender straitjackets we wear just a tiny bit.
Thank you for reading.
PS - Don't have 50 points yet and can't leave a comment but this needs to said.
@Upper_Case (replying to OP) writes:
I wouldn't classify those questions as anything like sexual coercion,
but it's a bit off that you are 100% committed to making sure she is
an eager participant in these activities except for specific cases
that are important to you, in which case you are disregarding her
You take the guy to task quite harshly considering it is impossible from his words alone to infer a serious breech of sexual etiquette, let alone anything worse. And then you pull a classic "I'm not at all accusing you of X BUT..." move. That is so underhanded and uncalled for. If you had no intention of mentioning something, you would not have mentioned it. But you did mention it. That's kind of like me saying "I'm not calling you an asshole or anything, but there's something really distasteful and sleazy about your attitude." No, technically I am not calling you an asshole, but effectively that is exactly what I'm doing. Hypothetically of course.