A guy took a fancy to you at the party and the mask convinced you to suck his cock anonymously. You didn't tell Damara as you thought she may get upset you were being shared.
His cock was hard and thick in your mouth and the outfit constricted around your face only helped with heightening your excitement. You sucked him till he was ready to blow and when he did you forced it down your throat as far as you could swallowing the evidence.