Democrats Chris Coons (Del.) and Joe Manchin (W.Va.) were officially sworn in as Senators on Monday, joining the chamber on the first day of the lame-duck session.

Both men won special elections to fill seats previously held by two prolific legislators. Manchin, who stepped down as governor of West Virginia, now occupies the Senate seat held for nearly 52 years by Democratic Sen. Robert Byrd, who died in June. Coons, who most recently served as the New Castle County executive, now holds the seat held for 36 years by Joseph Biden (D), who stepped down to become vice president. Democratic Sens. Carte Goodwin of West Virginia and Ted Kaufman of Delaware temporarily held the seats until permanent replacements were elected.

Biden swore in both men Monday, but the former Senator was doling out advice to his Democratic colleagues even before they took the oath.

“He said to make it as physically uncomfortable as possible to spend the night,” Coons told reporters earlier Monday. “Get a cot in the office, or rent something small and cramped and unpleasant because there will always be pressures to stay.”

Biden, who like Coons had young children when he was first elected, famously commuted by train between Washington and Delaware every day during his Senate career. Coons said he would likely adopt the same tradition.

“His point was you have the best of intentions right now, but if you get a nice place, the first year it’s one night a week, the second year it’s two nights a week, the third year it’s three nights,” Coons said. “He says four years from now you’ll miss every game your son plays. I thought that was very insightful.”

Coons and Manchin are also participating in the new-Member orientation this week for the 14 other politicians who will officially join the chamber in January.