Can't pass througth sertain arrousal treshhold.

It could be a lot of things, you might need to try different ideas.

It could be the case that there's some deep mental resistance, where you're not giving yourself permission on some unknown level. Which might be something really obscure. Or you could be trying to steer things, when instead, the time has become right to let the session take on a life of its own. Maybe you're too locked-in to feeling pleasure in one place, or pleasure of a certain kind, whereas the sensations could evolve into something else, maybe something entirely new. Maybe you're feeding the session something it doesn't need anymore, like you've gotten to a stage where it just needs you to be quiet, hug yourself, stop thinking, and feel cozy. Crossing over into a release phase of an orgasm can feel very different than the pleasurable build-up stage, so you can't get tunnel-vision on one kind of sensation, or expect the orgasm to "take" you in the way a traditional orgasm would.

It could also be that you've got some wrong expectations about what the next level looks like, and you're stuck waiting to feel something that isn't coming. Like you might be used to feeling A then B then C, and if you're stuck at A waiting for B, you might just be able to skip straight to C, but it's such an unfamiliar transition that you don't believe it's possible, or can't even imagine how to shift there. Some of my best peaks had me feeling like "This isn't how it's supposed to work, is this even allowed?!".

These are just random suggestions, but there are many weird and unexpected things going on.
Like one phenomenon that keeps coming up for me is a tender lower-belly. When things are going very well in a session, I feel a distinctly new sense of relaxation in the area just above my pubic bone. It's such a deep relaxation that it makes me feel especially vulnerable in that area, like I'm worried someone is going to punch me there, that I'm too off-guard. And I have that thought every time. Lots of odd little details waiting to be noticed.

Not to be discouraging but it took me years to get where I am today - experiencing lots of intense pleasure and many Os and super Os but it’s been worth the wait! For me it was trying to force things and failing to totally relax and focus on the basics but it’s all come together! I searched for the ultimate toy thinking size was important but now basically any toy yields intense pleasure - even Aless gives me intense satisfaction!

Thank you guys! I will try to implement it

I hesitate to give advice as the only expertise I have is with my own body, but I did thought of a couple of things that might help you. You didn’t say how you got to the wall but you’re certainly doing something right! When I get to the plateau (I don’t think of it as a wall) and things aren’t moving forward, I often change the massager to a larger one and it can make the difference. Vocalising also helps. 

A recent experience of mine may give you pause for thought. I’m a retired guy with rheumatoid arthritis so I usually have my sessions in bed, but on this occasion I intended to have an ejaculatory orgasm as well. For some reasons I won’t go into, I decided to start the session sitting on the sofa. I got to the point where I was grinding and thrusting down onto the massager faster and harder. I knew it was time to move to the bed so I could really let myself go. I stood up with the massager still inserted and moved towards the bedroom door. I live on a houseboat so the bedroom is no distance away. I wasn’t half way there when my SO began. I was wonderfully shocked that the change of stimulation to something so gentle could provoke the SO. I could only wonder what I would have felt if I had to climb a flight of stairs! I certainly think it would have been fun trying to get to the top. 

I know it’s hard wired into guys that harder and faster will take you over the edge, but now I know  ‘it ain’t necessarily so’.  So when you think you’re on the plateau and stuck, get up and have a walk around. It may do the trick. 

Good luck on your quest mate. Hope all this may help you on your way.