lower unit
A nice female rear end that is unusually close to the ground when she walks, possibly because of short legs. More commonly used in reference to the storage compartment on a fishing boat.
(Girl walks by)
Guy 1: Godzilla, check out the lower unit!
Guy 2: Damn, that IS a lower unit!
Guy 1: Godzilla, check out the lower unit!
Guy 2: Damn, that IS a lower unit!
blown lower unit
when a woman has a droopy vagina
her twat looks like a blown lower unit