Courteney Cox guest-starred as Jerry's "wife" in this episode just 6 months before Friends (1994) debuted and launched her career to new heights.
Kramer's arrival at his girlfriend's place with darkened skin is a reference to Ted Danson's appearance at the Friar's Club (a few months before this episode aired), in which he caused a scandal by appearing in blackface, an idea suggested by his then-girlfriend Whoopi Goldberg.
Although a shower has its own drain pipe, as does a toilet, both pipes eventually connect to the main drain line, so George has a valid point.
George asks Kramer if he "goes" in the shower. Kramer replies that he takes baths. In The Shower Head (1996) Kramer complains about having to take a bath when his shower head was replaced with a low-flow model.
Elaine also receives mixed signals from a man at the health club in "The Jimmy."