Why do I dream about my online boyfriend? He became handsome and hugged him as soon as he met, but his voice changed and he stammered. This dream ...

It's because of missing.

I'm not an expert in dream interpretation, but I can feel that you are looking forward to seeing him. The rotating hug means that you will be happy to see him.

As for the latter, I don't know. After all, it's a dream, not real. If he stutters in a real scene, I would say that he may be too nervous and excited.

Anyway, good luck with everything.