Found a lump in my colon—what should I do?

So, my son is five now. About a year and a half to two years ago, my wife and I noticed that whenever he’s using the bathroom, this little bump pops out near his rectum. It’s not there when he’s just hanging out; it goes back inside on its own once he's done. Just wondering what we might be looking at here. Hopefully it's nothing serious, because honestly, the kid seems totally fine and super energetic otherwise.

It could honestly be anything at all, or just nothing special