Despite what the name might imply there is a different drink made in St Lucia which is said to have certain characteristics which give you a chubby.
It is made from the bark of a tree and you can buy it in the duty free shop at the St Lucia airport on the way home.
From the wikipedia page-Bois Bande is the bark of a tree (Richeria grandis) in the Caribbean Islands. It has potent aphrodisiac qualities. Ideally, one should steep it in high proof liquor for several weeks and then consume.