That feeling you get get when you actually feel your ejaculate being sucked back into your body - so much so that it actually cools your body and sends shivers down your spine. That, ladies and gentlemen, is the negagasm.
The other day, I asked my bitch to make me a sammich... after she had finished the morsel, she put it in front of me... longingly I looked at it, feeling that something was wrong... NO MAYO?!!! Bitch nearly gave me a negagasm!!!