I do believe the rules are simple: There is NO opting out allowed.
<of course this is a party & you can rp that your are in the bathroom or were, etc. -just in case of a long absence & if you have to get skipped> :/
On Your turn (which is whenever someone else isn't asking and as long as everyone there has gotten a turn) you ask someone present to choose either "Truth -or- Dare"?
TRUTH is a question they must answer TRUTHFULLY
DARE is an action you tell them to do. THEY MUST.