The word "popka" is Russian slang for one's posterior.
Yakov asks Sonja "Who pitched the third game in 1983 World Series and what was his ERA?" Starters were Mike Flanagan for the visiting Baltimore Orioles with a 3.30 regular season ERA and Steve Carlton for the Philadelphia Phillies with a 3.11 regular season ERA.
Both female guest stars, Barbara Cason [Rebecca] and Diana Brooks [Sonja] appeared on the series Scarecrow and Mrs. King; season two and three respectively.