As for me, I have not been spanked that much in a sexual situation. However, I did once get spanked by a female Dom in front of her husband who also got spanked by her. He was spanked before me and he did get very aroused and actually came while he was being spanked.
As for me, when it was my turn to get spanked, I did get rather hard, but did not cum. When the spanking was over, she told her husband to finish me off by masturbating me until I came. It was only about another minute or so until I did come and extremely hard when I did. Yes, she watched as her husband did this to me.
As for spanking we both got, they were with her open hand and were not that bad. It only made our butts a little bit red and no really severe marks. All of the marks went away in about a half hour. As for the redness, it took about two hours for our butts to regain their normal colors.
HOWEVER, I did spank a female one time, not with my open hand, but a ping-pong paddle. I tied her down to her bed face down stretched out very tightly. Her hands were tied to the bedposts and her feet tied together at her ankle and then to the bottom of the bed frame. She could not move. I sat down next to her and started spanking her with it. A first, she did not cry and only moaned a little in pain. As I continued hitting her with that ping-pong paddle she started to cry a little. I stopped and gave her a brake of about a minute and then I resumed the spanking. When it was all over, her butt was not just red, but a deep purple color and there was some really good welts on her butt. It did take a few days before she could sit down comfortably again. Even then the marks and welts lasted about two weeks before her butt started to return to normal.
As for her liking it, she did tell me after it was over and while she was still nude, that she knew she deserved it and was not about to ask me to stop before I decided to stop. A few months later, I did it to her again.
YES, she consented to it in full both time that I did it to her. After the second time she told me that if I ever wanted to do it to her like that again, she would willingly submit to it. She liked to be hurt that way.