MiniBiddy

The minibiddy is a form of sexual mail between partners in which they take turns mailing takeaway boxes filled with feces to eachothers house to eat then placing the resulting feces after 4 to 8 hours into a new container and mailing to partner again

Can be done in larger groups

Me and my friends had a round of minibiddying last month I had to stop after the mail man came to my door looking like he had eaten his way through a chocolate wall