Gaining

I think it can be fun! I'm a 300lb 6'3" guy so anyone next to me looks pretty small especially a smaller girl. It's only more apparent as I gain weight.

Definitely am! I think the size difference/contrast is one of the main turn-ons in this fetish for me. Although personally i'm fit myself and i like my women big

I absolutely love size contrast! I love being able to pick up, lift, carry my GF. Size contrast is all around the best!

It's the best! I miss being with someone with big contrast to myself since i'm so big already....

Tall with a big pot belly, tall and skinny.

Where I really love size comparison is not between myself and someone else, but between someone who looks really fat by herself, but would look small next to someone even fatter. For example, fantasizing about having an enormous girlfriend who has a fat sister or friend, who complains about her size, and then my much bigger girlfriend has fun that she is fatter but doesn't mind it.
Or better yet, getting to know a fat girlfriend who has even fatter sisters. And after some time, the sisters gain weight, and people think at least now my girlfriend won't look big in comparison.. and then she enters, much bigger, having overtaken them in weight and becoming the biggest.

My wife has a sister who is huge (275'ish), had been fat since she was about 13 and then blew up in her 20's. And it was great to see the size comparison of them when my wife was bone skinny.

Now it's awesome to see them both as fatties, pounding beers and snacking - laughing and having a great time. It's as if it was inevitable one of them was going to become either slim or really fat as an adult. Luckily mine became a happy piggie, too.