Best bikini bottoms for flat butt?

I have a large bust, but my butt is prettyy flat and I feel self-conscious about it. I would like to get some flattering bikini bottoms so I'm not constantly worrying about it at the beach this summer. I heard that ruffles are good... but I don't really like the ruffle style that much. Any other styles that would help it look a little perkier? Also what style is best for big thighs? Thank you!