1. Being in unfamiliar territory.
2. Vagina spasms which resemble a fish gasping for air. This can be acomplished in many ways but the face down on the floor with an ironically wet orgasm most resembles a fish out of water.
also note:
There are plenty of fish in the sea... meaning theres a lot of hoes out there or there tasty fish to nourish your soul.
Contary to other definitions slapping a beauty with the beast in the face is actually called a classic bitch slap not a fish out of water.
Last night, Becky was so hot and bent that she had a fish out of water for my dent dick.
Cory Edwards dick is so fucking hott! I had a fish out of water when I saw that juicy head... I was like fill up my belly button like a sweedish gas station.