It's been several years now since we've done the wine tasting on board. In general wine tastings are fun events during which you may find that you like certain wines better than others. You'll probably sample 4 or 5 wines. They will be very small pours, an oz or two. Just enough for you to sip.
You'll also learn how wines can compliment specific foods. Typically you sip some wine, take a bite of something (usually cheese) and sip again. The "bites" are also very small portions.