Danish Helmet
A Danish Helmet occurs when a lady of impeccable pedigree slips whilst receiving oral pleasure in a standing position from a bald man whilst on the rag. As the lady is falling, her crucifix becomes dislodged and lands on the top of the man's head just prior to her box. The result is a pattern on the man's head resembling the Danish flag.
So I was going down on this classy Dane, she slips, and the next thing you know I am wearing a Danish Helmet.