Expiration dating refers to starting a relationship that has a defined end date; for example, one of the people is moving soon.

“到期约会”指开启一段有“截止期”的恋情，例如，其中一方不久就要搬走。

Example:

"I hear you started dating some new girl."

"Yeah, but she's moving across the country in a month, so we're planning on breaking up."

"A little expiration dating, eh?"

“我听说你开始和新的女孩约会了。”

“是啊，不过她一个月以后就要搬到国家另一端居住了，所以我们计划到时候就分手。”

“你在玩‘到期约会’啊？”