1. What does it mean?
In gaming, 버스 treats the strongest player as a driver and the others as passengers. 버스를 타다 means benefiting from someone else's work to clear a stage or win, while 버스를 태우다 means carrying others.
Also written or said as beoseu
2. The nuance
It can be a grateful joke among friends or criticism of low contribution. It does not automatically mean a paid boosting service, and game-specific rules still apply.
3. Examples
“어제는 친구 버스 타고 어려운 던전을 깼어.”
Yesterday my friend carried me through a difficult dungeon.
“이번 판은 내가 버스 기사 할게.”
I'll be the one carrying the team this round.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.