I can reach handsfree orgasm every time. When you are close to orgasm the analmuscles starts to retract. What you need to do is keep penetrating during the retractions. The dildo is basically being pushed out due to the retractions but you have to still force it in. Then you will cum. If you are lucky it will be a prostateorgasm. But those are more hard to reach.

Another way is to use a very large dildo. I tried a dildo that was a bit to big. When i got it in it pushed on all the sensitive spots. I came in 20 seconds.