In English, reaching orgasm is expressed by many phrases – “Bingo”, “Yahtzee”, “Team Rocket is blasting off again”, etc. However, none are more common than “I am coming”. In Japanese, it is expressed by saying “I go”(行く). There are many mistakes made in Japanese, as they confuse sentences such as “I am going to the store” and “I am reaching orgasm to the store”, and these oftentimes find their way into English lessons.
When the student makes a mistake, confirm meaning by having them demonstrate with their hands. 99% of the time, they mean to express “going” and not “reaching orgasm”.
To practice the difference between the two English meanings, you may practice a roleplay where the student travels throughout a city and reports their activities to you via “phone”. This roleplay should only focus on the literal English meaning of “go”. This will help the student avoid saying anything particularly embarrassing when using English outside of the classroom.
Japan really needs to redefine their slang.
With so many people from the international community coming to and coming in Japan, saying “I am going” just creates confusion.