Third day of the week, honoring the element pungent.
Arise early (ish - before 12pm is usually seen as polite, but it's not set in stone or anything, so don't worry about it unduly. 6am is ideal). Be sure you haven't bathed since last Pungenday, throw open your doors, windows, what-have-yous and praise Eris loudly thus:
Hail Eris, Goddess of the days! Sniff me on this Pungenday! Be sure I whiff suitably, like a mangy badger's arse after a long sauna! Whoof!