As the song reaches its peak, you add a complex rhythm on the bass drum. The song feels full and the other band members are having fun. You all finish the song and the audience cheers.
You manage to keep up through the next few songs. This is tiring work.
Eventually, the bass guitarist lets you know there's only one more song. You've really gotten into the groove of playing, and are even able to add in some drum fills in the last song.
Afterwards, the band members thank you for helping out and begin packing up. You head out, exhausted but satisfied with by job well done.