When a person has an std, specifically gonorrhea or chlamydia, and ejaculates in someone. The person creampied may grossed out by the resulting green jizz.
Girl 1"OMG, Jason didn't pull out and it was all green and gross"
Girl 2 "damn, getting a shamrock creampie is the worst"
Girl 2 "damn, getting a shamrock creampie is the worst"
by Crimsondeath798 February 14, 2017