
Can someone explaine the joke at ch. 21 page 8, when he said do you want to see how old I am (or adult or something) and pulled his leg up and pulled on his pants?

But she said something about an "old joke".
I think it could be something language related. Just today I read a manga with some lame jokes, it could be something similar. In Warewate wa Neko de Aru, chapter 6, a cat is making puns, for example "The cat laid down", because in japanese it seems to be "Neko ga nekoronda" (translated in the same page, I can't understan japanese).
It is surelly something that has to do with the japanese culture.
What's the names of the mangas at page 20 of chapter 48? Especially the one with the cute boody