Wasn't this in a Ludacris song?

Postavit' rakom - lit. "to do it crayfish style". Missionary.

Story time, kids.

Once upon a time, I used to work in a grocery store that was popular with Russians. Some of them befriended me, and would give me all sorts of advice on how to live. The first time I heard someone using the expression "v kusty i rakom" - "in the bushes and crayfish style" - was when a man was advising me to go to Russia for a long visit, because the girls are hot, fun, and generally behave like gay men in San Francisco in the 70's. As evidence, he described his own adventures picking up random girls and doing things with them in random places. His wife and kid were waiting for him outside, so he hurried off before the true awkwardness of my needing to say something back set in.

Addendum: As multiple people have commented, it's actually doggy style.
Addendum 2: I don't know any of said people. Which means that it's not just my friends reading this. It's enough to make me want to update more often.

Don't hate the player. Please. He's not personally responsible for our confused mating habits.

K bahbeh prikolotsa - lit. "to pin onto a broad."  Prikolotsa, which literally means "to pin onto", usually means that you're going to engage in charming/annoying/absurd exchange of wit with another person, usually a stranger.  When applied to an attractive member of the opposite sex, it means that you are going for the charm offensive prior to making a pass, with an option to make the whole thing a joke for your and your friends' amusement should the pass be deflected.

In Soviet Russia, Cuckoo's Nest Flies Over You

Psihushka - lit. "the shrinkery".  A mental institution.

The Sweet Science

Mordaboi

Let's break this one down:  

Morda, as mentioned in a previous post, is a rude way of saying "face".

Boi means "battle" or "combat".  

Mordaboi, if translated literally, means "the application of combative intent to someone's mug", or, if we were to make sense of that, a "brawl."  

Nowadays, it's shorthand for MMA.

When a simple "fuck off" is inapropos

отвязаться

otvyazatsa - lit. "to get untied from".  To leave alone.  "Ovyazhis' ot menya" - lit. "untie yourself from me" can mean anything from "too busy chillaxin' to talk about this" to "whatever it is you want isn't gonna happen right now" to "fuck off and die, you unbearably irritating cretin".  The tone and emphasis determines everything.

And We're Back

Ladies and gentlemen,

in honor of the idiom-stopping shenanigans of recent days, this one is going to be

зубодёр

zubodyor - lit. "tooth yanker" A dentist, usually an artless one.

Two things to remember about Soviet dentistry:  It existed in a primitive but pervasive way; Anesthesia pretty much didn't.  Serious root-work was out of the question, but they could cap, pull, and replace your teeth with steel ones.  The zubodyor was not your friend.  Or anyone else's.  At parties, he didn't tell people what he did for a living.

That's all in the past, though.  Nowadays, dental tourism is a pretty decent reason to visit Russia.  For some reason - perhaps the huge market of people who have never had the benefit of orthodontia - the zubodyori have really taken to modern methods and equipment and become a industry of dental surgeons notorious for their skill and relative detachment from first-world medical cost inflation.

A Proper Russian Send-off, Pt. 2

Idi v zhopu - lit. "go into an ass".  Equivalent to "go to hell".  Soviet society enjoyed state-enforced secularity, so normal ways of telling people off - "may demons take you" or "go you to the devil" - were not exactly in vogue.  Hence, a non-religious, non-superstitious bad place to send people to. Whose ass is never specified. Hence, when translating the expression into English, the idea of the Collective Ass, appropriate to a collectivized society, is introduced.  "Go burrow in the asshole of mankind" would make a pretty sweet neologism.