Nothing, but similar to other accounts a small sensation of knowing what it should look like without the visual.

Shocked when I learned my immediate family member can actually visualize things without even closing their eyes which lets them essentially 'trace' what they're envisioning.

My best friend also is incapable of seeing things with eyes closed - they were a bit upset when I brought it to their attention.

Interestingly enough, of everyone I know I have the most vivid, engrossing, lucid dreams. Guess all that brainpower when sleeping saps the power supply for during the day.

My significant other only dreams in Black and White, which was more mindblowing to me than seeing black.