When someone accidentally or intentionally pisses the bed in the middle of the night while sharing the bed with someone else. They do not notify the other occupant and allow them to roll in and sleep in it throughout the night.
When you fart and you're in the bath tub, and all the bubbles float to the top very slowly, and then when it hits the top, you can smell your own brand.
Mary made a mexican bubblebath when she was in the tub, and passed out after the bubbles surfaced, releasing the noxious odor.