Been trying on/off for about 5 years now. Some questions

1) I've seen a few videos where people shake. I sometimes try to let my body 'go' but worry I'm trying to move too much. I've heard of people getting O's without hardly any movement. Is this possible?

I wouldn't give too much importance to those XXX videos, while some men do experience their prostate orgasms in such a manner, many do not, individual variations of reactions are unique to each individual. If you try to duplicate someone else's experience by imitation, you will very likely fail in frustration and miss the opportunity to experience your own genuine, unique, natural body reactions. Early on in my own practice I would get only some light muscle tremors and to this day (after 9 1/2+ years) I still do not get shaking even with my Super-O's. So, YES, it is entirely possible.

2) At point I tried looking at stimulating images, I know this is a big no-no but it seemed to help? I don't touch myself, but I was looking at them which seemed to initiate a wave. But then I would stop looking and fully concentrate on the feelings which is what I've ready is the key, I wonder if I kept looking at visual stimulation if it would work better for me? Is it even worth trying or should I be fully focused on my body?

IMHO, viewing porn before initiating an Anerosession may prove beneficial in generating your arousal, but viewing while in the midst of an Anerosession is distracting and pulls your focus of attention away from your own body to following the scripted action in the video, (please see the user Poll Are you aroused by porn?). I think you are better off focusing on the sensations your own body is sending you while you engage in your own inner fantasy world.

3) Curious. If I had previously traditionally masturbated to orgasm a hour or so before does that affect the possibility of an anal orgasm? or would it be worth trying not to masturabte for a few days before trying this? or are they both disconnected from each other?

If your masturbation resulted in an ejaculatory orgasm then, yes, it will very likely negatively impact your ability to achieve any kind of orgasm in such a short time frame due to the male refractory period. Ejaculations trigger a hormonal cascade which affect mood and physical response, this usually includes a drastic drop in one's arousal level. I believe practicing some form of temporal absinence (semen retention, tease & denial, karezza, chastity, Taoist practice, etc.) increases one's arousal levels making dry orgasms easier to achieve (see Aneros, Arousal & Abstinence). Orgasm and ejaculation are separate events, learning to disconnect their traditional association and causes will allow you to become truly multi-orgasmic.

4) During my last session I got worried as my testicles/bladder seemed really 'full', I really needed to pee so I gave up. I was then wondering if that's a normal symptom of this activity? Was it right to stop or should I have carried on. I feel like I was close 🙁

A filling bladder puts pressure on the prostate which activates the same nerves as are stimulated by your Aneros massager, as long as that pressure remains constant you will continue to have urinary urgency, especially when using your Aneros, this is totally normal. Feeling comfortable that you are not going to lose urinary control while you drop into a relaxed orgasmic state is important, if you feel uncomfortable (for any reason) then stopping your session is the best action. I recommend avoid drinking any fluids for at least an hour before and then completely voiding your bladder immediately prior to beginning your Anerosession. Providing yourself with towels to lay upon and have handy is also recommended. Taking those simple precautions will enable you to relax into the nerve stimulation being provided by your Aneros without worrying about accidently urinating. It is important to allow yourself sufficient time for your body to build into the orgasmic zone. Having to stop before getting to that euphoric state is frustrating so try to eliminate the worry and distractions. Good Vibes to You !

Great advice that I will try and put into practice in future practices, thanks for taking the time to respond in great detail.