On stage at the International Brotherhood of Electrical Workers' conference in Washington, DC, "creepy uncle Joe" Biden, as he is known among his detractors, hugged the union's president Lonnie Stephenson.
Afterward he spoke with reporters about the recent controversy.
Answering questions from reporters after the speech, Biden said he was "sorry that I didn't understand more".
"I don't see Joe Biden as a threat", Trump said.More news: Teen tells police he’s missing boy Timmothy Pitzen, last seen in 2011
Flores told CNBC she felt Biden's attempts to "make light of something as serious as consent degrades the conversation women" are having in the #MeToo era. I'm not sorry for anything that I have ever done.
Biden recounted a time when he said the dignity of teachers, sanitation and electrical line workers was treasured and the nation felt it had a common goal.
And, highlighting the tension between Biden and other forces within the Democratic Party, he again complained about attacks from "the far left" over his pledge to work with Republicans should he be elected president. "What we can't do is blow it up".More news: US Democrats officially request Donald Trump's tax returns from IRS
I've worked my whole life to empower women. "He has been a leader and a champion on fighting violence against women for many years, and I have been fortunate to accompany him to events with survivors where he has listened to their stories, empathized with them, and comforted them".
Friday was the second time in two days the president attacked Biden on Twitter.
During the 2016 campaign, at least 18 women accused Trump of sexual harassment or misconduct, alleging everything from unwanted kissing to walking through women's dressing rooms at the Miss USA pageant to putting his hand up their skirts.
Asked why he was waiting to announce his presidential run, Mr. Biden said that, if he was running, it was always his plan to be "the last person to announce".More news: Watch NCAA Tournament Game Online