This is why I use the following release form when entering into any serious bondage scenarios.
"I, the undersigned, heretofore and forevermore do solmnely swear, that I am not a blood-sucking vampire and have no intention of stabbing or otherwise causing blood to flow from the body of my precious subbie, and have no intentions whatsoever to suck, drink, consume or otherwise nourish myself or other kindred from the bodily fluids rightfully owned and posessed within the corpus of said precious subbie, excepting that such bodily fluids as may be freely provided through ejaculation are fair game; nor will I undertake to harm my slutty little plaything unless within the bounds said slutty little play specifically and willfully grunts out in the affirmative; and I also respect his need to hold the TV remote control for many hours after any bondage session, regardless of how intensely his channel selections may suck in my opinion."
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Mistress ____________________________.