Replying 'cause I also want to know.
I am almost sure it has something to do with the hair in the legs, but I don't get how that would be a joke.
Same. Hope someone can explain
Itd make sense if it was referencing his leg hair because leg hair is a good representation of biological maturity. I think the joke is him offering to flash his body to her (hense “you like that dont you”)
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.
Pretty sure he was just pretending to do a lil strip tease by slowly showing off his leg like a stripper. But thats just MY take on it.
But it really is an old joke tho...
So, what is the joke exactly?
Well,,, its exactly as @Unicatrus said-
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?