I only stutter when I have to explain something or tell a story

I only stutter when I have to explain something or tell a story Why is it that I can say any curse word I want, any stupid phrase, and it comes out like butter. Honestly, for my whole life, I've been "that guy who just makes noises" cuz when I am out w/ friends, I just say random dumb words and we all laugh (especially funny when we're drunk). I rarely ever have deep convos with my friends, cuz once I do, I start stuttering. Somehow, when I just want to tell like, a funny story that happened at the gym, suddenly I can't even say a single word. My brain gets really tight, and there's no word I can say other than curse words, and then I just say "f this, nevermind I'll say it later". That's what I do around my family. Then later in the day I am able to say it after stuttering for like 90% of it. But hey, it got out I guess. With friends though, I really make sure the stuttering is as "hidden" as possible, so firstly I try not to even get in the situation of telling a story. But if I am in the situation, I have to use so many different strategies to get the story out, like "starter" words such as "well" and "I mean...". I like fake cough in between words too, laugh, or take a sip of water. This is just really frustrating at this point. Don't really know what to do.