Since "ball"ing is a common slang term for having sex, it means simply having sex outside in the snow.
My lady and I had a snowball last night. I don't know if it was the chill on the backside (initially shocking, but extremely erotic for some reason), or being outdoors under the moonlight that made us so excited.
por Panchoman Jr. 17 de Novembro de 2006
Being drunk enough not to notice the onset of slight freezer burn occurring while having intercourse in a snow bank.
“Melissa was put on bed rest for a week by the university doctor after Saturday night’s snow ball, I wonder how her mystery partner is doing?”
por reginaandray 16 de Fevereiro de 2007