The bot mentioned above just makes a post for you, so unless you can't be bothered to make the bump post yourself it isn't really necessary.
The only way to bump without making a post is if the topic has not been posted on for at least 6 hours, a 'bump' option will show up on the bar under the thread;

However this only shows up once, then another post has to be made + another 6 hours will no posts for it to show up again.
Some users if they do not want there to be a bunch of bump posts on their topic will limit it to just one bump post by deleting the previous bump post before making a new one. As long as the last post on the topic is yours you can delete it, but if anyone else posts after you than you won't be able to delete your previous replies on the topic yourself.
Just keep in mind to not bump unless your topic has fallen off the first page of that board (and deleting your previous bump to make it look like it fell off the first page of the board when it didn't isn't allowed, its fine to delete previous bumps just keep in mind its not a freebie to just bump whenever you want)