Yes, there are many positive alternatives. For example, adventure stories that can inspire people's sense of exploration. Stories of friendship can teach us about loyalty and mutual support.
Mainstream literature is supposed to appeal to a wide range of audiences, including children and the general public. Butt plug erotic stories are clearly not suitable for such a broad readership. They are more likely to be found in adult - oriented or underground publications that are not part of the mainstream literary world.
Sharing or seeking such erotic content is inappropriate and not allowed in many platforms and communities. We should focus on positive, healthy and legal forms of literature and stories.
One success story could be for those with certain medical conditions like pelvic floor issues. Some people have reported that using a butt plug, under proper medical guidance, has helped in gradually strengthening the pelvic floor muscles. This in turn can lead to better bladder control and overall pelvic health.
I don't think they are that common. Sexual experiences like using a butt plug are very personal and often not something people casually talk about. There are taboos and privacy concerns associated with it. Also, different people have different levels of acceptance towards such sexual exploration, so not many would openly share their 'first butt plug sex stories' if any at all.
Well, the first time using a butt plug can be a very strange experience. You might feel a bit of discomfort at first. But if you take it slow and use plenty of lube, it can become more comfortable. It's important to relax your muscles too.