Richard Garriott, one of Austin’s most interesting and accomplished entrepreneurs, is willing to tell you the truth about pooping in space.

Most astronauts will happily explain how the simulator works and how it works in space. But they leave out the details of the experience, perhaps out of courtesy for those easily grossed out or maybe they’re just embarrassed.

Garriott, who created a commercial space flight company and bet his life savings on a trip to the International Space Station in 2008, told the story in polite detail during the kickoff party for Austin Startup Week 2017.

He explains that the simulator used in trainings doesn’t work the same way it does in space — gravity, it turns out, plays a key role. Without it, your digestive system works infrequently. But when ya gotta go, ya gotta go.

We’ll let Garriott explain in a way only someone who’s been there can.

Here’s the video (you’ll never think of toothpaste in the same way again…):