"I was a late bloomer, for me it was 16," he said.
Vieira replied, "I don't think that's so late!"
Chmerkovskiy grew up on the outskirts of Coney Island in New York and "things progress a lot faster," he added.
"Whatever the situation is, as long as it's wholesome and it's right," he continued. "It's still an experience you look back and say, 'I was an idiot, but it was awesome.'"
He added, "Mine was with a supermodel, who ended up lying about her age. ... She was about 10 years older than she said, that made her into like early 30's. It was amazing."
Vieira said she was older, but in high school and it was with a boyfriend she had for three more years.
The dancer also shut down a "misconception" about making love.
"Girls always expect the birds and everything," he said. "It's like every time you have sex, you have to have a basket of pigeons that you like let out."
Chmerkovskiy retired from "DWTS" in July after winning the Mirror Ball trophy.