Within a Consort, during peak estrous, and immediately prior to Mounting, the Guarding male using his forehead to push an estrous female, from side to side and forward, while she Stands-to-Mate. May sometimes be observed by younger males in a Social Play context.
References: Eisenberg et al 1971; Poole 1999a; Poole & Granli 2011. (Full reference list)
This behavior occurs in the following context(s): Courtship, Social Play