When you're doing a chick in the ass and she gets diarrhea and it squirts out all over the place. Kind of like when you stick your thumb in the end of a hose nozzle and the water shoots out forcefully.
Rich: "So how was fuckin Lauren last night? I could hear it going down in the living room."
Adam: "Well it was good till I stuck it in her ass. Then i got the old Thumb in the Hose Nozzle action and spent the rest of the night cleaning up your leather couches."