A phrase used for those special occasions (ie. Birthday, Christmas, Anniversary) when a woman bestows your wishes and gives the gift of swallowing, rather than her norm of spitting.
I have been avoiding asparagus and garlic and pushing the pineapple and candied ginger, I have a Swallowday this week.
Her: Hey what do you want to do for your birthday?
Him: I'd like to catch a game, hit a few bars then celebrate my Swallowday.