"The chart comes from Mona Chalabi’s fantastic post on “the gender orgasm gap“. While only 64% of women say that they climaxed during their last sexual encounter, more than 90% of women who received anal sex say that they reached orgasm at some point during the entire sexual encounter.
So, what’s going on here? Does anal sex make you come more than other kinds?
Finally, to state the obvious, there are no sex organs in your anus: you’re very unlikely to come from receiving anal sex alone. But that’s not what the data says — it’s simply saying that when a woman receives anal sex, she’s very likely to have an orgasm within the same sexual encounter.
The most likely explanation, I think, is that anal sex heightens the impetus towards reciprocity, a key concept in all social science, including economics. If someone does something selfless for you, then you feel obliged to do something for them in return. This data is telling us that when a man has anal sex with a woman, the woman is in an economic sense doing a favor for the man. More than any other sex act, anal sex causes a man to be as determined as possible to make sure that the woman has an orgasm."