I've noticed that, in daily conversations, when people are telling stories in the past, they often shift the tense back and forth between the past and the present - even they're native speakers. For example, people might say:
_It was almost 5 a.m. He hadn't come home yet, and his phone was off. I'd been so worried that couldn't sleep at all. Then I heard the door knocked fiercely. Of course it's him. He's got a bottle of whisky in his hand and smelt like a tramp. He stumbles in, ignoring me at all. I was like, stopping him, asking where he's been. He suddenly turns around, shouts at me, pushing me crazily out of my flat and locks me out. I am totally petrified. I've never seen him like that. That's why I asked you if I could come here._
I made up this scenario because I couldn't come up with an exact example I've heard, but it happens all the time. The tenses shift. On one hand, I don't have any problems understanding the story. I wouldn't misinterpret the timeframe just because I heard the tense jump to the present. But on the other hand, I would feel a bit uncomfortable and think, "isn't it wrong?." Furthermore, when it comes to me telling stories, I've been struggling with this usage. I can't judge if this usage is proper, educated, and "correct." Also, if this is proper, are there any rules I should keep in mind so that I won't confuse the listeners? Should I insert something like "I was like" from time to time to remind the listeners that I'm still talking about the story in the past? Or should I shift to the present tense only when I tend to bring the scene more lively to the listeners? Is it a good idea to tell the whole story in present tense once the time has been set, in this case, after the first sentence? Finally, since I feel the present tense is generally easier to be spoken more fluently, would it be recommended to use the present tense throughout the whole story, given I'm sure the timeframe has registered with the listeners?
Any suggestions will be greatly appreciated.