Jill Biden had been speaking to a crowd and gesturing with her hands when her husband leaned forward and nibbled on the tip of her index finger.
In response, Jill Biden laughed it off. He's repeatedly mixed up the states that he's campaigning in, while his lackluster debate mishaps have garnered him much negative press. (Though he is one of four septuagenarians in the Democratic primary running against the 73-year-old incumbent, Biden's frequent gaffes are pointed to as evidence of his decline as a public speaker.) The use of old-timey Irish-American slang is unlikely to shore up his support among young Hawkeye voters, though it could be a call to his majority in the state: Only 5 percent of Biden's Iowa supporters are under 45.
Biden was in Iowa for eight straight days of campaigning to thwart a slide in public opinion polls that has benefited Buttigieg, who leaped into first place in some recent surveys there. "And there's a long way to go in this campaign and we talk about the polls, at this point, I don't think they mean a great deal", Biden told reporters during his Iowa trip before Thanksgiving.
Behind the optimism, Mr Biden's aides acknowledged that he must sharpen his message and bolster his voter outreach operation ahead of the caucuses that start the Democrats' 2020 voting. But his advisers also insist he has wide support and remains well-positioned to recover any lost ground.
His chief argument - his perceived strength against Mr Trump - was on clear display last Saturday. Sidestepping his philosophical tussle with progressive Sens. He added an emphasis on small town and rural America, an electoral swath where Democrats have struggled in recent elections but that could prove critical in both the nominating fight and November battlegrounds. The former Obama agriculture secretary recently gave Biden his most high-profile Iowa endorsement. As Jill Biden introduced him to a crowd in Council Bluffs, the former vice-president put his wife's finger in his mouth.
The latest Iowa polls show Biden competing almost neck and neck with Sens.
Other candidates in Iowa this week include in mayor Pete Buttigieg and senators Elizabeth Warren, Bernie Sanders and Kamala Harris. The senators have animated the party's left flank, while Mr Buttigieg joins Mr Biden in the Democrats' centre-left wing but is calling for generational change.