Basically, a nipple.
As for the origin of it, in the anime called "No Game No Life", Sora, the main character, played a game of word chain, and he said "chikubi", which is "nipple" in Japanese, so the translators had to come up with a word that links "beach" and "bikini", and that's what they created.
At the bar:
- Damn, look at dem hooter nubs over there
- I know, mate, just leave it to me, and we'll have some threesome in no time
another term for a station wagon, mini-van, or any other kind of vehicle that is targeted at the "family" demographic(also M.A.V.)
"Tactical advantages aside, the M.A.V. is top of the line for the holy warrior troop transport manufactured by the Church of Latter Day Saints Military Industrial Complex. Also great for family trips...to heathen lands."