You and your partner dabble in a spot of anal, only for the receiving party to let rip and spray shit all over the giver.
The giver is then so disgusted by the taste of shit that they throw up into the hair of the receiver, ensuring that it drips down onto the bed and ideally the carpet.
Oli had a bad curry and whilst mid throws with Ben and farted. Ben was covered in shit and threw up in Oli's hair, and they had a Sheffield Shagpile on their hands. Not sure if Oli then partook in a Sheffield SickPie.