Bukkake Shotgun
A Bukkake session in which all giving participants ejaculate in the same direction simultaneously. The force and angle of the blast is much like that of a shotgun, making the receiver's head snap back uncontrollably, due to the pressure of the stress. The givers should abstain from any sexual act for as long as possible prior to the session to achieve maximum effect. Also, participants with natural superhero-like ejaculatude tendencies help the snapback effect.
Last night, we had a Bukkake session in which we all timed it correctly to give Shiva a neck-breaking blast, aka, a Bukkake Shotgun. She is still walking around like her spinal cord was ripped out.