[SuzyQue]

Kegebuns? Never heard of them. What are they?

[GSlob]

"Kegebuns? Never heard of them. What are they?"
A pun in Russian, playing on the phonetics of "KGB" pronunciation, with the last part of it forming the root of the ef-verb. That's how we used to refer to KGB types. Literally, KGB-effer. And "kegebuchest' is KGB-effing.