It's important to listen carefully

I went for lunch with my teachers today. Very enjoyable in fact, we went to a restaurant I have never been to before and it was a good mix of people. As usual I understood a few words of the conversation here and there, or the general gist of what was being said. Or I thought I did. The teachers were talking and they mentioned 'Satoko', a common Japanese woman's name. So far so good. However the next word I understood was 'chinko' the Japanese word for penis (the reason I know this word is far more complicated than you could imagine and is not from the usual dirty words are fun to learn strain of studying). So i am sitting there in this conversation, wondering why my teachers are talking about a penis and a woman, given that they would only normally discuss this kind of thing with close friends, i.e. not with work colleagues over a bowl of soba. Eventually i decided to raise this with the Maths teacher on my left (who incidentally was the one who was speaking and mentioned the words together). She starts rolling with laughter. Literally rolling around in her seat, alternating between hitting m shoulder and burying her face into it. Somewhere in the middle of this the other teachers start to wonder what is going on, at which point the maths teacher splutters 'jinko' before dissolving into fits again. Inspiration dawns, they were not talking about penises. They were using a word which i had never heard before (incidentally which means population for anyone interested). So with the maths teacher incapacitated it is left to me to explain. The male teachers roar with laughter, however the other two female teachers remain slightly unimpressed. Oh well some mistakes are destined to happen. On a daily basis. Sometimes it is important to listen more carefully.