I'm not 100% sure but I believe the website was called pregnant pg-13. It was where people like axel rosered got their start.

Anyways I remember two pictures on the site from one piece. 

The first picture I remembered was Nami and her sister bumping bellies on their tangerine farm. 

The second I think was just a few different women using their devil fruit powers to keep Buggy's floating hand.

I know this isn't much information to go off of and the site probably got shut down a decade or more ago. 

But if anyone still has these pictures or know the artist who drew them I'd appreciate it. 

I don't think axel was the artist and I'm pretty sure they were black and white.