Originally Posted by CjTheFish

Like Lolipop suggested I have had great success using Crowdfire to build active twitter accounts across a wide variety of niches, including adult.

Here's a strategy that might save you a few bucks since Crowdfire does cost. If you download their mobile app and link your twitter account through the app and unfollow or follow your first 100, it will then prompt you to upgrade to premium to increase the limits. Premium costs around $10 a month, but from what I've experienced only on mobile after your first 100 it will give you the option to have unlimited follow/unfollow limits for a full year for only $5. With that you also get the auto DM's without the crowdfire watermark which can be useful for your marketing needs.

The best way to gain right off the bat, (apart from tweeting excellent content) is mass following and unfollowing users. You can follow up to 1,000 a day and usually you can expect to recoup 10-25 percent of that in terms of follow backs. What do you do with the rest? Just unfollow them

Crowdfire offers a feature where you can mass follow other accounts followers, but from my experience I get the most followbacks from seeking out similar accounts with large followings and massing off the favorites on their recent tweets. You can do the same for retweets however I find that in adult, a lot of the retweets are simply just other accounts in the original tweeters network.

Good luck!