Vampire Sunday
The act of going down on a girl on a Sunday while she is on her period and getting blood around your mouth, once enough blood is collected you proceed to bite her neck before she can realize the blood on your mouth. After biting her neck you look at her in the eyes and yell "Vampire Sunday"
I went down on my gf while she was on her period, I got her Vag blood all around my mouth and proceeded to bite her neck before she saw the blood. I then looked at her, blood around my mouth, her neck hurting, and screamed Vampire Sunday..