sniff out
to seek someone or something as if by scent
If they think they have sniffed out some secret, they need to take a closer look at the details. (example of sniff out)
Sniff me out
A request for someone to bring their nose/mouth close to their genitalia; a request for oral sex.
"Sniff me out like I was Tanqueray" from the Amy Winehouse song "You Know I'm No Good"