My husband says it's a totally different type of orgasm. There was no stroking,sucking or any other stimulation. Just anal/prostate stimulation.
After massaging his prostate with the head of the dildo I would tease his asshole by popping the head of the dildo in and out, then deep in again pushing gently on his prostate. Precum oozes out of him like a leaky faucet all the while he is taking it. With the dildo all the way in, I will give it fast and short movements right on his prostate. He tells me that he can feel it building as he squirms around on the dildo. When he does orgasm, he shoots very strong and with more cum than his other orgasms, which are big to begin with.