The scent of a lover, left behind in one's bed after their lover has departed. This might be the lingering scent of shampoo or deodorant, or caused by... other things.
"Oh, I've got it so bad... as soon as they left I jumped straight back into bed and went searching for some good shniff..."
A play on the phrase "Scratch and Sniff" Smelling your own fart by cupping the air around your butt with your hand, after farting, and bringing it to your nose.
I hope my farts don't smell too bad ... I'm going to have to "Catch and Sniff", to make sure, because I have a hot date tonight.
When a male rubs his hand along his scrotum, and then proceeds smells his hand--now scented with his ball musk--, he has just performed a Sack Sniff. Often performed, but rarely acknowledged in polite society, the Sack Sniff is an interesting cultural sensation that begs for an evolutionary-psychological explanation. The male executing the Sack Sniff will often report enjoying the scent, or at least conceding that he finds himself executing the Sack Sniff frequently. Perhaps he is checking levels of pheromones in his system as a form of virility/fertility auto-monitoring behavior.
Male 1: Did you really just wipe your balls with your hand and then smell it?