A "slushy" is an extreme act that is not for the weak hearted! The act is performed by a man ejaculating into their partner's mouth. The partner then swishes the semen around in their mouth and mixes it with saliva. This solution is then spit into the male's butthole where it is to be fermented with his fecal matter by jumping and twisting motions. After 20 seconds of mixing, the male pushes the matter into the partner's mouth. This excretion is dubbed "slushy."
I took this girl home from the bar last night and we made about half a gallon of slushy on three occasions!