Umm, it's impossible to play tennis in the rain. The ball gets wet and bounces different and starts spraying water when it rotates. Practicing in the rain was all a sham to get into his pants and he knew it!
Clearly we're gonna get a sequel. Not just one but multiple sequels. He's got to get sloppy seconds from the other sister. He's got to get both sisters at the same time. They also have to explain the whole mother thing. I've got high expectations man.
That scene with Hozumi is another time from the one in inequality sign. She's got braids this time. Also, it was Akira who suggested that they follow Hozumi when she disappears but was shot down by her other friends. Looks like she did tag along and peeked on them too.