I bought two and both were on their way out in just a few days. Boy, they sure don't last very long.
I didn't dry out the seeds as people do, because, pffft, why? They germinate right inside the tomato on the counter when I don't get to them so enough, and I figure this is how nature intended. The white stuff is food for the seeds, not for us.
The seeds work best with sunlight to germinate. So everyone says. That means best on top of the soil. But I sprinkled the merest possible layer of soil on top of them. Only one granule thick.d
The seeds absorb moisture and form a gel around them like chia seeds do. Say, an even teaspoon of seeds will absorb 1/4 cup water. If you'd like to see a dude completely freak out about that, here. After watching the guy run his fingers through the non adhesive gooey mass, another dude in comments wrote, "I think you need to be left alone with your seeds. Ha ha. Just kidding."
So they're in their little dragon fruit terrarium.