The Death of Stalin - Spend a Kopeck??? 
Near the end of movie, as Beria is being detained, Molotov says he's going to go "spend a Kopeck." He sort of rubbed his belly and said something like 'it must be all this excitement..' Thus it seemed pretty clear he meant he was gonna go "drop a deuce," as we say.

A Kopek, by definition seems to be a coin, 1/100 of a ruble. Urban dictionary listed it as "a fuck," but I have no fucking idea what that's referring to.

So where does the phrase come from? Am I correct that it means to take a dump..?

Thanks! Stay classy y'all 🙃