Good posts. I won't restate things already said. One size doesn't fit all so you can take the views and see which ones resonate with your experience and situation. I am assuming you mean you are fucking and it doesn't seem to be exciting you in the way that you feel you will be able to ejaculate anytime this week?
It could be simply that the position you use to fuck doesn't give your cock enough stimulation, although I LOVE the view I get with fucking doggy but I find it doesn't give me the best stimulation for the most part as I am average length but thick so I don't get as deep as some. For me the bottom on his side on the bed, top leg pulled up to 90 degrees and me one leg on the bed between his legs, one on the floor and cock pumping his hole gives me much better stimulation. The bottom reaching back and squeezing my nipples kinda completes the deal and a hot wet cumload up his hole is not that far away
I had difficulties like this for a while. Thinking I HAD to cum for the bottom, and concentrating on the feeling of my cock in the hole - my thoughts centred around my crotch - and finding I was not being able to cum. So I was not thinking about myself in the context that I was concentrating on delivering for the bottom, but was totally thinking about myself in being centred on my inability to perform as I THOUGHT I should perform. When all is working well then you will no doubt be there with bottoms queueing up to get the pleasure of serving your cock, and you will derive your pleasure and big squirty orgasms from doing, so big time. That's a hot thought!
I learned that for me I was too much in conscious thought. Thinking about whether you will cum or not is you being in conscious thought. You really need to be having a 'party in your head' with the fantasies, sensations and dirty thoughts all happening in your mind. Feelings should be felt in your head and you should not be thinking about the mechanics of what you are doing except for imagining yourself fucking the ass off him and dumping a massive load which will drip out and run over his balls, and manoevering yourself and him to make it so! It should be the pleasurable thoughts around what you are doing, or what is happening, that you are concentrating on in your mind - if your attention is diverted into reality like your penis feeling like it is getting floppy or your ass getting sore then that will become true and it won't work until you get your thoughts back inside your head again. If that happens take a break and remember real life isn't a porn film - it's much better because you get to direct it yourself... that's what I learned in overcoming it anyway