Near the end, Joe and Quagmire are shown sitting at a booth inside the bar with Joe pulled up to the corner of the booth. As Peter apologizes to them, Joe is no longer seen next to him. As Peter takes Quagmire's check, a part of Joe is seen sitting in the next booth. In the shot after, he disappears again.
The showgirl hints that Peter got her pregnant although Peter had a vasectomy in "Sibling Rivalry".