Noun or Verb. Vaginal and anal double penetration: Occurs when a woman is being penetrated by two men - one in the vagina and one in the anus, giving the appearance or feeling of being stitched by a sewing machine.
Jeff: Hey, man, where's your wife? I thought she'd be at the party.
Ben: She's probably off stitch fucking Stacy and Josh again.
Jeff: Jeez, again? I thought she did that this morning.
Ben: Yep, she sure loves her some stitch fucking.