Yiddish has a reputation for being a dirty language, and maybe it's because a lot of people who knew some Yiddish, like my father, liked to swear in it. It's also a language that sounds like it should be dirty, as it is composed of the same sort of hard, Germanic consonants we rely on for so many English cuss words, coupled with a sibilant softness, a shushing noise that sounds insinuating, like somebody is whispering in your ear, and everything they whisper is galling.
I have not found it to be that dirty a language, and often surprisingly modest. One of the Yiddish words for vagina is "dortn," which just means "there." Another is "sphiel zakh," which means plaything. Others? Knish and peirog, which are just names for food, and are no more inherently vulgar than calling a penis a sausage. Jews curse a lot, and they do sometimes tell people where to shit (on the ocean) or fart (in their own throat), there are fewer of these sorts of phrases than there are curses like this: "Go take a bath!" Or, "I have you in the bathhouse!"
For some reason, Jews like to included baths in their curses.
So there is a word for the sex act, and it's was popular enough in Yiddish to find an English-speaking audience, and it sounds like a curse word. The word is "shtup," and, as you probably already guessed, it's not much of a curse word. The word is used regularly in Yiddish, and usually when it is used, it is used to mean "push."
A lot of language does this -- takes an innocent verb and, because it calls to mind something dirty, presses it into service to describe sex. We don't have sex with a piece of wood when we screw it, or, at least, most of us don't. These are, at worst, mild swear words, the sort of phrase, like "jumping their bones," that is used in G-rated films to describe coitus.
There is another word, treated in Yiddish as far dirtier, far more vulgar, for the sex act, the equivalent of our F word. That word is "yentz," and its most literal translation is just "that thing." So, as I said, Yiddish speaking Jews could be unexpectedly modest in their use of curse words.
I'm sure I heard the word "shtup" from my father, but my clearest first memory of the word is from the 1982 film "My Favorite Year." The film follows a young Jewish television writer as he must shepherd a drunken proxy for Errol Flynn, who is to appear on a filmic proxy for "Your Show of Shows." At one point, the young Jew, played by Mark Linn-Baker, brings the Flynn proxy, played by Peter O'Toole, to meet his cartonish Jewish family. Around the dinner table, an uncle, played by the great comic actor Lou Jacobi, presses O'Toole for details inspired by Flynn's rumored romance with a 15-year-old. “That paternity rap a few years ago," Jacobi asks, "did you shtup her?"
The website English Language & Usage charts the general popularity of this word, noting that it started gaining traction in the 60s and really took off in the 80s, about the time of "My Favorite Year." They also note that before that, its appearance in English tended to be nonsexual. As an example, in Clifford Odetts "Awake and Sing," a character says "I shtupped him a ten-dollar bill," meaning about the same as "I slipped him some money." There's nothing terribly surprising about this usage if "shtup" means "push," although it does create a surprising image is "shtup" means "have sex with."
But by the 60s, the word had undeniably joined American slang as a word for sex, as in Julie Bovasso's 1963 play "Moon Dreamers," where a police chief confesses "I was shtupping! I was shtupping!" When a French character asks what the word means, he's met with a dismissive, "You're a Frenchman and you don't know from shtupping?"
There is a part of me that want to credit every Yiddishism that entered the English language in the 60s to Leo Rosten, author of "The Joys of Yiddish," but in this case I suspect the author who gets a lion's share of the credit is Philip Roth, who used the word a few notable times in his bestselling comic novel "Portnoy's Complaint," where it seemed perfect for the whole leering, uncontrollable sexual pathology of the book. Incidentally, the film version of "Portnoy" starred Richard Benjamin, who directed "My Favorite Year," so Mr. Benjamin may be the actor most associated with shtupping, linguistically speaking.
Some samples of the use of the word "shtup":
Dark Waves and Light Matter: Essays, Albert Goldbarth: "'They come, these shloomps, they don't know if their breath is like a chazzer's tuchus' a swine's ass 'but their head is filled with the shtup shtup shtup, so nu?' She shrugged. 'So I get filled with the shtup shtup shtup a bissel mineself.'"
Fifty Shades of Oy Vey: A Parody, E.L. Jamesbergstein: "'This conversation has really helped me,' I whisper. 'I think we could shtup now.' 'Yes, Anatevka,' he breathes. 'You and I, we both want the same things. Let's shtup.' My breath hitches. My skin flushes. In the room next door, a toilet flushes."
Approaching Oblivion, Harlan Ellison: "Besides, meaning no offense, I don't shtup with strangers. It wouldn't be such a good thing for you, either, believe me. Everybody says Evsise is a rotten shtup.I got very little feeling in my pupik, you wouldn't like it, not even a little."
The Return of Stewie Stein, Stan Weisleder: "They were shtupping everybody and everything, male, female and transvestites, they didn't care in the least. Not one bit. Marlene Dietrich wasn't shy at all about her escapades. You might even say that she flaunted them."