Have sniffed a few panties of friends who have left them lying around at my place or in their bathrooms when I've visited. Makes for intense orgasms. If a girls doesn't bother to try to hide them or put them away properly, why not?
Years ago, a very sexy friend of my **** left some on the floor in the guest room one weekend she stayed over. Discovered them when I was home alone the next day (was about 20) and jerked off with them over my nose. Huge load from the smell of her lovely pussy in my nose. Still one of my favourite friends of my ****.