I was cocking up this lady, face to face, when she says: "I know a different way I'd like this." So I pulled out of her puss and started working my way into her anus. After awhile, I am all the way in and start working her ass. She starts squirming and panting and moaning. Suddenly, she arcs up, crying out, and pisses all over me and the bed.
She was embarrased, but I was okay with it and told her so. Later, she told me that she had never pissed during orgasm, but then she had never had such a big cock in her ass before, and the orgasm was just too intense. She never pissed again during sex (despite plenty of orgasms), either with vaginal or anal, and I was, truth told, just a little disappointed.