I want extravagant lashes what should I ask for?

I never had lash extensions but if I had some done I would really want something extravagant. Tips for what I should get? I’m thinking about getting them for summer though I’m scared it will ruin my natural lashes(I have pretty long and thick). How long do they usually last and will they harm my natural lashes? Can I still use lash serum even though I have extentions?