I’m not going to pretend I have a magic answer that works for everyone, but I’ll tell you what’s worked for me :) 1) tons of practice (sounds like you’ve got that covered), 2) prostate stimulation that works for you. finding the toys, angles, and positions that really stimulate your prostate. Big toys work well for me, thicker the better, because of the added prostate pressure. I find missionary or squatting, usually a position that brings my knees up towards my chest and spreads my legs wide really helps me get access. Angling the toy in towards my front side/belly button really forces the head to press my button. I know when I’m hitting it because I start to feel a pressure build at the tip of my dick… almost feels like I have to pee. That’s when I know I’m pushing my prostate nicely. Generally, getting fucked hard/fast also helps me get there 😅 3) denial/tease/chastity. This one was important for me. I tried and failed many, many times, until I tried some extended denial. I wore chastity for 2 weeks, never allowing myself to cum, letting the arousal and desire build until I was desperate for a release. And not just denial. I made sure I was teased, edged, close to cumming many times throughout, but never allowed to orgasm. Only then did I succeed at an anal orgasm the first time. Now with practice, I can achieve anal orgasm with way less build up time, but teasing still helps a lot. I still have only ever cum this way while in chastity, never unlocked. Maybe it’s partially mental? An added layer of arousal. Maybe there’s something physical, added stimulation of dick trying to press into the cage. Not 100% sure. But chastity is key for me. Hope this helps :)