A sexual position or maneuver in which a male inserts a glass or Pyrex-based test tube into the anus of his partner and then proceeds to masturbate into the test tube, filling it with semen. He then executes a well placed donkey punch
, causing the partner's sphincter to contract, effectively breaking the test tube, thus bursting into an explosion of blood, shit, semen, and glass shards.
I gave Julie a Mad Scientist last night. I nearly lost an eye in the explosion!