聚会派对上的“暖场客人”

A buffer guest is a close friend that you invite to a party ten or 15 minutes before the rest of the guests are scheduled to arrive. 
Buffer guest指关系较近、聚会时要求比其他宾客提前10到15分钟到场的朋友。我们可称之为“暖场宾客”。

This guest or group of guests is meant to 1) make it seem like the party has already begun and good times are to be had, and 2) make it less awkward in case someone you don't know particularly well arrives before everyone else.
安排这一类暖场宾客主要是为了：让后来的宾客感觉聚会已经开始，欢乐时光正在继续；如果有主人不太熟悉的宾客提前到了，也能帮着调节气氛。

For example:

I invited Jona over as a buffer guest in case Tim or Josh came over early, because I don't really have a lot in common with them.
我请了Jona过来做暖场宾客，以防万一Tim或Josh早到，他们跟他们又没什么共同话题。