horn

blow (or toot) your own horn talk boastfully about yourself or your achievements. North American

draw (or pull) in your horns become less assertive or ambitious; draw back.

☞ The image here is of a snail drawing in its retractile tentacles when disturbed.

1991Paul GrescoeFlesh Wound Hollywood's major studios were pulling in their horns in the wake of a disastrous Christmas season.

lock horns: seelock.

on the horn on the telephone. North American informal

on the horns of a dilemma faced with a decision involving equally unfavourable alternatives.

☞ A mid-16th-century source described a dilemma as 'a horned argument' (after Latin argumentum cornutum), the idea being that if you avoided one 'horn' of the argument you ended up impaled on the other.