For all you youngsters out there, "piles" is an old (World War 2 and before) term for hemorrhoids (At least in American English). I used to get them too but I haven't had that problem since I started transition.
So if we are talking about anal penetration, we need to address the "H" word as well.
I don't have any magic cures for that one but I can offer this with respect to the penis: My last few years as a man I had a lot of anxiety and confusion about orgasms with the penis. I've fixed that by dissociating any thoughts of being male from its use and concentrating on my own femininity.
So assuming you have no physical issues with regard to that particular organ, you may need to address psychological issues in terms of associating it with being male before you can think of achieving orgasm with it.
Now for a final nugget of wisdom: for a woman, the orgasm originates in the brain, regardless of the source of stimulation. In order to have one, you need to feel relaxed and loved, even if only loved by yourself. The physical sensations, whether from breasts, anus, or elsewhere, are just cues for the orgasm machinery in the brain to fire up and get going. This is why there are reports of women going to the emergency room having nonstop orgasms, and being diagnosed with manic phase bipolar disorder. Bipolar is a brain chemistry disorder, and the orgasm originates in the brain.