Why do you make the assumption that guys are sniffing underwear during the day? :wtf:
What I do is: I sleep with a chick and I tell her the panties stay when she leaves. That way next I jerk off before I see her again I have something to remind me of her.
I don't think I would have the need if I was living with someone I was screwing.
How old are you you, and how many women do you bonk per month?