The 'Couples Retreat' actor was horrified when he went to a class and saw the "creepy" instructor draping himself all over his unsuspecting students.
The 39-year-old star said: "I had a girlfriend in Los Angeles who took me to a yoga class. While it was going on I was saying to myself, 'Is this really happening?'
"It was like the instructor was making all these moves and he was basically dry humping the girls. Nobody batted an eye. I felt like I was in 'The Twilight Zone'."
Vince who is currently engaged to Canadian real estate agent Kyla Weber also revealed what he looks for in a girlfriend, saying he likes someone who can make him laugh.
He added to Parade.com: "Friendship is the biggest thing for me, and also a sense of humour. I like someone that can make me laugh. I like to laugh at stuff, especially myself.
"Life is always peaks and valleys, there's going to be good times and bad times. So the biggest thing, for me, is having someone that makes you laugh and that you trust.