Tiki mug
An opaque ceramic vessel, usually figurative, for tropical rum drinks. Worth knowing that the form is an American commercial invention of the mid-twentieth century rather than a Pacific tradition — the drinks are serious, the iconography was borrowed.
What it's for: Serving tiki-family drinks over crushed ice.
Don't have one?
Any tall opaque tumbler. The drink is unaffected; only the presentation changes.
Ceramic insulates better than glass, which genuinely helps a crushed-ice drink stay cold. That is the one functional advantage; the rest is theatre.
Buying guidance
Many vintage and reproduction designs reproduce Pacific religious and cultural imagery. Plain or abstract designs avoid that, and the drink is identical.
Cocktails served in this glass
7 recipes call for it as their glass of choice.

