How can I (20F) have a conversation with my boyfriend (25M) about his tendency to cut people off in conversations?

So my boyfriend and I are long distance and most nights we end up using FaceTime to talk. Whether it’s on the phone or in person, he has a really bad tendency to cut people off mid-sentence and interject something he wants to say. I’ve asked him politely before not to cut me off, and I know he doesn’t do it intentionally. He’s a really enthusiastic person and has a shorter attention span, so I think he may just be saying things before he forgets. Regardless, is there a way I can talk to my boyfriend kindly about this without upsetting him? I’m really non-confrontational and not very good with my words in the heat of the moment, and I’m afraid I might upset him if I just out of nowhere say something.