This usually takes place in an office or party situation when someone drops a toxic deuce right before you use the bathroom. When the next co-worker/fellow partier walks in after you innocently drain your bladder, you get the judgmental scowl and embarrassment. At this point there is really nothing you can say to get out of it as you have just been shit framed.
"Man I got totally shit framed at the party last night in front of this hot chick. I went in to take a quick piss but it smelled like someone ate the entire contents of a used diaper filled with Indian food then subsequently shit it out right before I walked in...so obviously the hottie I was talkin to the whole night walks in right as I walk out..."