It's when you shit after sex and cum comes out mixed with crap because you were just fucked silly in your ass.
comes from guys getting rapped in jail and having a jail baby when they go to the bathroom.

Slang term for juvenile detention center.

Slang term for a crib or playpen.

The place where you can put a baby if he/she is being bad.

Aka: Pack-N-Play

When you get soft-locked in Super Mario 64, i.e. getting stuck in a spot that you can't move or escape but also can't die and you have to quit out of the game. Shoutouts to SimpleFlips

Popularized by Twitch streamer Simpleflips, Gay Baby Jail is a spot in a game where you are softlocked and unable to leave. This extends to not being able to die, forcing you to load an old save file or just turn off the game.

A softlock in Mario 64 rom hacks where the only way out is to restart the game. Most of the time this is unintentional and is caused by developer oversight or general laziness. However, despite this, according to the twitch streamer who popularized this term, SimpleFlips, "Gay baby jail has never been a tangible location, its always been apart of you. A state of mind, a state of being. Solids, liquids, gases, gay. baby. jail."