5 pak of assorted nipples.  Funkify your VapoHead!  Different colours different days, seasons, or whatever...... most importantly, if you are sharing your vapo at a party - give everyone their own plastic nipple - they can take them out each time the vapo comes their way.  At the end - everyone put their mouthpiece into the dishwasher to be cleaned (or by hand) for the next vapoparty!