So how exactly do you strangle someone without any special items, feats or abilities?
The Aerial Servant has the smother ability, which hastens suffocation, but it relies on the victim having to hold its breath. Constrict, grab, and grapple, are silent on suffocation, as are Air and Elemental subtypes. CRB suffocation rules are silent on ways to cause it.
So how would an Aerial Servant, in a normal room, with lots of free PC air, get this ability to work.