Well, I’m suggesting that you add a message inside your app, or on your site, to explain what you are going to use the Twitter login permissions for - so it is really up to you how easy that might be! There’s no way to customise the message inside the Twitter login page itself, it will always show “Read tweets” and “See who you follow”, since that is what read-only permission potentially enables you to do, even if you are not doing that.