Herbert: Mamacita alert! Danny, get a glance at this specimen!
Danny's head spins 360 degrees to survey the horizon
Danny: Oh Herbert, you really know how to spot em'
Herbert: Da fuck is up with your neck!!! I'm calling the exorcist!!
That sneaky look over your shoulder to see if anyone just heard (or smelled) your fart.
Having eaten too many beans for breakfast, Michael let out squeaky fart just before the opening hymn at church. A fartive glance at the old lady behind him indicated that she had heard and smelled his squeaker, and she was not impressed.
When a small group or crowed suddenly realizes that someone has emitted a silent but nasty fart and they all look among themselves for facial expressions or body language that might pinpoint the perpertrator.
The group by the bar was festive, but suddenly all was quite, and everyone was looking among themselves with farting glances.