I tried this for the first time a couple weeks ago. I was on vacation with my best friend who is straight and his family. We were sharing a hotel room. He left his worn underwear out after changing into his bathing suit to go to the pool. To my disappointment, I didn’t smell anything in the crotch area. It’s like his underwear was fresh out of the laundry. I don’t get many opportunities to have access to his worn underwear. Oh well.