This ritual is intended to be done using seedling paper ("Seed paper is a type of handmade paper that includes any number of different plant seeds. The seeds themselves can still germinate after the papermaking process and they can sprout when the paper is planted in soil." —Wikipedia).
Write a note on seedling paper to your own body, thanking it and saying what you need to say to it. Plant the paper, and after you plant it, say the Kaddish. Then celebrate your uterus by having uterus-shaped cookies and things that are red. Surrond yourself with friends and/or family to help you bury your "uterus" and experience the grief of its loss, but also allow space for some joy.