Chris Harrison reveals behind-the-scenes details on set of The Bachelor!

"One of the great mysteries is how do the roses stay on at the rose ceremonies," Harrison jokes to PEOPLE of the men's boutinnieres. Turns out, they're outfitted with strong magnets to secure them to the guy's lapels – and to save the Bachelorette from sticking herself with pins every week." Check out Chris Harrison's behind-the-scenes video at!