In my human sexuality class, my instructor asked this question to the entire class room because he stated that although all three are enjoyable, studies have showed that people actually finds one of these sexual activities more enjoyable than the other two.
My instructor was right because besides a handful of girls, most of the girls in the class stated that they find masturbation to be more enjoyable and satisfying then oral sex and sexual intercourse. This wasn't surprising to me, because if you think about it there are a lot of female masturbation toys out there and in today's society women aren't really that shy or ashamed about using them or telling people that they use them.
I knew what most of the male students’ answers was going to be because my answer was the same, most of the male student stated that they find oral sex (getting a blow job) more enjoyable and satisfying then masturbation and sexual intercourse. The other male students said that they find masturbation to be more enjoyable and satisfying then sexual intercourse.
Considering fact that 95% of the guys in my class are straight, I can see why they chose the answers they chose because you have to work at getting to that point of extreme sexual arousal during sexual intercourse, and I pretty sure that the girls they have sex with usually start off by giving them blow jobs before the main event, and from the time they're getting a blow job they're becoming extremely sexual arousal themselves and when it's time to pleasure the girl (sexual intercourse), they only have a few minutes before they are ready to cum. At that point, the girl is left unsatisfied and the guy has gotten off and is completely satisfied. Which leads back to why all the girls chose masturbation, self-satisfaction.
What is your answer to my question?