So Ive had oral before, and I enjoy it a lot ;)... When it starts to get intense, by body(Mainly my lower half) kind of starts to twitch(more like spasms). I will tighten up my body to stop the spasms but then I end up pushing up against a wall or a bed post really hard. Is this a sign of an oragasm or the guy being really good?

How old are you?

18

Have you been able to bring YOURSELF to orgasm?

The reason I ask is this: Once you've had an orgasm, you KNOW it.

Indeed. If you had one, there's no question that you know you've had one. It's a feeling that has no words to describe it.

I would agree in the main that orgasms are normally self-evident but with a caveat.
Females can have different kinds of orgasms depending on the site and type of stimulation as well as on how they are feeling. The way the orgasms feel and their intensity can vary a lot even for the same person. Sometimes this can be confusing even when you are experienced sexually.

The main thing I would say though is why worry? If you are having a good time enjoy it. It is possible to have orgasmic sex that isn't actually mind-blowing and it is also possible to have great sex without an orgasm. Obviously it's nice to have the whole deal but if you are having fun and don't worry about it you're more likely to have an orgasm anyway.

If your consciously stopping the twitching, try not to. Hopefully, it will feel even better. All females don't orgasm in the same way, nor with the same technique.
In many cases oral is easier than penetration to achieve orgasm.