Chinese idiom

I want to explan the idiom of "人走茶凉" to help foreign friends to understand the Chinese culture.
This idiom means when a people leave a company, a place or hometown for a new life, at the beginning, the friends or colleagues will you contact you and you also want to talk to them about your new life and the happiness and the unhappiness. However,  as the time goes by, the realationship will become weaker, and you will not contact with your friend and your colleagues, and your friends also don't contact you. that isn't This doesn't mean you don't want to talk to them. It is just because they don't know what they should to say with to you. It is very awkward when they call you but and silent. So if you want to meet describe this scene you can use the idiom of"人走茶凉"