Wandering PineExcerpts from Manual
"Rest – sit out your turn to sober up, removing one hangover token. The party carries on without you."
Rest is an action during the entertainment, not the morning after. On your turn you could stay in and drink with people to win their favour – or step outside, clear your head, and sit this one out.
It's a more honest version of "pass": even doing nothing is something the night asks of you. And the party does not wait.