The modern Tongan recipe is most well-known today is usually a blend of water(1cup), cream of one coconut (1), shredded coconut meat, and any variety of grated tropical fruits, most commonly watermelon(1/4 of medium size), mango and pineapple(1), with watermelon being the most used in the Tongan Islands. Sugar is usually added to taste.
Tongan historians have noted this version is a very modern take on the traditional Polynesian ʻotai, especially since milk, refined sugar, watermelons, mangos, and pineapples are all introduced, foreign ingredients that were not native to Tonga. The original Tongan recipe was said to be identical to the Samoan recipe, except the preferred native fruit was not ambarella (vi), but the Tongan mountain apple, called fekika. In Samoa, this distinction of “native” and “introduced” recipes is differentiated as “ʻotai” only refers to the drink prepared with vi fruit, while the ʻotai made with European-introduced fruits are respectively called vai meleni (watermelon drink), vai mago (mango drink), or vai fala (pineapple drink).
The mixture was poured into large, empty coconut shells corked with coconut husk and allowed to chill in cold pools of water (or behind waterfalls) before serving.