Noun
1. A woman who upon exiting the saltwater has seaweed, kelp and several small invertebrates trapped in the gusset of her bikini bottoms. This ecosystem should remain living there for no less than 2 days.
2. A term used to describe a woman's vagina that emanates the sulfuric stench combined with the fishiness of lagoon water.
"When I pulled off her bikini bottoms, the smell from her lagoontang was reminiscent of trips to the beach as a kid. Hey, there's spongebob!"