Exploring sexuality and [Anal Play], not feeling anything fro(m) it.

So, I'm definitely not straight, something I'm exploring more recently after repressing it for a few years after I became conscious of it around 18/19.

Recently I've been craving the D and I get this strange tingling sensation in my anal area which I feel like is associated to sexual arousal. I've assumed so far that this is my prostate. Well, to satisfy the feeling I've tried everything I can think of and have at my disposal reasonably (all with lube obviously), fingering, end of a hairbrush, toothbrush container, and cucumber.

The results are (sad and) hilarious, I get super aroused before I start, masturbate a little bit, and then get to the business. Well as I start I continue to use porn, etc. but as soon as the object goes in I feel nothing. I tried finding this so called G-spot and just nothing. I occasionally get a little bit of pain (nothing major), which is a turn off, but otherwise nada. After about a minute of attempting this, I get the overwhelming feeling like I'm going to shit myself and my butthole literally forces the object out. What the fuck is going on here? Why is my body feeling like its aroused, but nothing comes out of it? I end up having to finish normally, and just feeling like an idiot for a bit with a lubed up cucumber in his hands.