SWOP Share definition Flag Sex While On Period; an acronym that refers to having sex while a woman is having her period I hate to SWOP, it's so messy. SWOP by Tracy Kaply August 19, 2006 Words you can keep railfan mug chonk mug chud mug based mug 67 mug slime mug mogging mug chopped mug thot mug glazing mug huzz mug yams mug larp mug unc mug cracked mug simp mug baddie mug bop mug lolcow mug