I'd have to say that the hundreds of Rika/Satako (aka fucktoy) threads we have had have had for the past forever constitute the majority of the erection time I achieve on /a/. That is to say, if you measure, over time, the time I have had an erection browsing /a/, Rika and Satoko are responsible for over 50% of that time, which is quite a remarkable achievement.
Not only was Higurashi better than average, it nailed the loli thing down almost perfectly. Some prefer Rika, some prefer Satoko, a lot of people both, but one of them probably hit your moegasm spot. I mean, supposing you aren't a total faggot, which I know too many people on /a/ are.