Episode: "Comrades" (Season 2, Episode 1)

Philip (Matthew Rhys) and Elizabeth Jennings (Kerri Russell) have one of the strangest marriages on television; the couple are agents for the KGB, posing as a normal American couple. So their relationship is, in a sense, strictly professional before the beginning of the series sees Philip and Elizabeth growing closer and becoming increasingly more like a real couple, one that's arguably closer than similar pairs married for some years. By the beginning of the second season, Philip and Elizabeth are, more or less, invested in their marriage, something represented in the season premiere by Paige catching them engaged in "mutual oral sex." There are other scenes on The Americans with more explicit sex (especially between Philip's alter-ego Clark and his second wife, Martha), but this one is the most important. 69-ing is almost never shown on TV, and its depiction on The Americans is both a perfect way of capturing the state of the Jennings' marriage and some of the most realistic TV sex without descending into hackneyed tropes of awkwardness. Philip and Elizabeth aren't porn stars, but they're comfortable with their bodies, and that's pretty remarkable on its own. —Eric Thurm