Mouth approach
An individual brings its mouth toward that of another, while looking or smelling. The mouth is closed, contact may occur (Thierry et al. 2000).
In a clever set of experiments, Chauvin & Thierry (2005) showed that Tonkean macaques can use this behaviour to gain information about the availability of specific food sources and avoid searching themselves. In this video, the individual smelling the mouth of the female eating, was later observed eating the same food source. Because both individuals were already located on the food patch (the fruits were available on the ground), it is possible that the individual smelling what might have been an unfamiliar type food was then motivated to try it herself.
Chauvin, C., & Thierry, B. (2005). Tonkean macaques orient their food search from olfactory cues conveyed by conspecifics. Ethology, 111(3), 301-310.
Thierry, B., EL, B., Baker, S., Matsumura, S., Muroyama, Y., TG O, B., ... & Watanabe, K. (2000). The social repertoire of Sulawesi macaques. Primate Research, 16(3), 203-226.